CUET UG Mathematics Booster Test 2 - Inverse Sin and Inverse Cosine Functions
📌 Answers are locked once submitted — results and explanations appear at the end.
QUESTION 1 OF 20
If a custom function f(x) = sin x is strictly defined only on the interval [π/2, 3π/2], does an inverse function exist for it, and if so, what is its resulting range?
QUESTION 2 OF 20
Accurately match the following principal inverse trigonometric evaluations to their correct radian outcomes.
| List 1 | List 2 |
|---|---|
| 1. sin⁻¹(1/2) | a. π/6 |
| 2. sin⁻¹(−1/2) | b. −π/6 |
| 3. cos⁻¹(1/2) | c. π/3 |
| 4. cos⁻¹(−1/2) | d. 2π/3 |
QUESTION 3 OF 20
Which distinct pair of intervals below BOTH represent mathematically valid, bijective branches capable of defining an inverse sine function?
QUESTION 4 OF 20
Which of the following analytical statements is mathematically INCORRECT concerning the principal branch of sin⁻¹?
QUESTION 5 OF 20
An angle y is analytically mapped from the expression sin⁻¹(√3/2). What is the exact fractional numerical value of this mapping interval's principal output in radians?
QUESTION 6 OF 20
In the standard (x, y) Cartesian plane, the entire area strictly enclosed by the curve y = sin⁻¹x, the vertical y-axis, and the horizontal lines y = -π/2 and y = π/2 is bounded horizontally on its extremes precisely at:
QUESTION 7 OF 20
A processor computes y = sin(sin⁻¹x) for all inputs from -1 to 1. Because this relationship evaluates to y = x, what is the exact moving average of any two symmetrically opposed domain values (x and -x)?
QUESTION 8 OF 20
A continuous variable x is chosen completely uniformly from the interval [0, 2π]. What is the exact mathematical probability that the property sin⁻¹(sin x) = x evaluates as true?
QUESTION 9 OF 20
A spatial vector transformation T strictly swaps the components of any vector (x,y) to (y,x). If T is applied to every coordinate vector making up the locus of y = sin x strictly where x ∈ [-π/2, π/2], the resulting new vector locus defines:
QUESTION 10 OF 20
The region bounded by y = sin x (for x ∈ [0, π/2]), the y-axis, and y = 1 has an exact geometric area of (π/2 - 1). By utilizing the reflection along y = x, the integral ∫sin⁻¹x dx from 0 to 1 directly corresponds to this area. What is its numerical value?
QUESTION 11 OF 20
Because y = sin⁻¹x behaves as a strictly increasing function on the sub-interval, what must identically be the mathematical sign of the definite integral of its derivative over this exact interval?
QUESTION 12 OF 20
Assertion (A): The mathematical evaluation of sin⁻¹(2) strictly equals π/2.
Reason (R): The defined domain limits of the sin⁻¹x function strictly exclude any numerical values greater than 1.
QUESTION 13 OF 20
Arrange the following inverse cosine evaluations strictly in descending order of their numerical radian results:
1. cos⁻¹(0)
2. cos⁻¹(-1)
3. cos⁻¹(1)
4. cos⁻¹(-1/2)
QUESTION 14 OF 20
The exact mathematical solution to the equation cos⁻¹x = 2π/3 falls validly within the principal range [0, π]. What is the specific real value of x?
QUESTION 15 OF 20
If the expression cos⁻¹x is analyzed strictly in an alternative, valid branch such as [π, 2π], the corresponding function behavior on this domain is:
QUESTION 16 OF 20
By examining the analytical graph of y = cos⁻¹x, the specific planar coordinate point where the curve intersects the horizontal x-axis is:
QUESTION 17 OF 20
When analytically comparing sin⁻¹x and cos⁻¹x, evaluating the expression (sin⁻¹x + cos⁻¹x) for any value of x strictly confined within [-1, 1] yields a universal constant. This constant is:
QUESTION 18 OF 20
The identical domain similarity [-1, 1] necessary for defining both the inverse sine and inverse cosine mathematically originates from the fundamental fact that:
QUESTION 19 OF 20
QUESTION 20 OF 20
Test Complete!
Answer Review
1 If a custom function f(x) = sin x is strictly defined only on the interval [π/2, 3π/2], does an inverse function exist for it, and if so, what is its resulting range?
Sine is one-one on [π/2,3π/2]. Inverse exists on bijective intervals. Inverse range equals restricted domain.
On the interval [π/2,3π/2], the sine function becomes one-one and covers the range [-1,1]. Therefore an inverse exists. For inverse functions, the range of the inverse equals the restricted domain of the original function. Hence the inverse range is [π/2,3π/2], making option C correct.
- Option A → Inverse exists because sine becomes bijective on this interval.
- Option B → [-1,1] is the domain of the inverse, not its range.
- Option D → [-π/2,π/2] is the principal branch, not this custom branch.
Used: Contextual/Tonal Matching
Application:
- Apply inverse-function rule: original restricted domain becomes inverse range.
Final Logic:
- Inverse range always equals the original restricted domain.
"Inverse swaps domain and range."
2 Accurately match the following principal inverse trigonometric evaluations to their correct radian outcomes.
| List 1 | List 2 |
|---|---|
| 1. sin⁻¹(1/2) | a. π/6 |
| 2. sin⁻¹(−1/2) | b. −π/6 |
| 3. cos⁻¹(1/2) | c. π/3 |
| 4. cos⁻¹(−1/2) | d. 2π/3 |
sin⁻¹(1/2)=π/6 cos⁻¹(1/2)=π/3 Negative inputs follow principal branches.
Using standard principal values: sin⁻¹(1/2)=π/6, sin⁻¹(−1/2)=−π/6, cos⁻¹(1/2)=π/3, cos⁻¹(−1/2)=2π/3. Thus the matching becomes: 1-a, 2-b, 3-c, 4-d. Hence option C is correct.
- Option A → Swaps positive and negative sine inverse values.
- Option B → Completely mismatches standard principal values.
- Option D → Incorrectly exchanges cosine inverse values.
Used: Substitution
Application:
- Recall exact trigonometric standard-angle values.
Final Logic:
- Principal values directly determine the matching.
"Half gives 30°, negative half gives −30°."
3 Which distinct pair of intervals below BOTH represent mathematically valid, bijective branches capable of defining an inverse sine function?
Valid branch requires one-one behaviour. Sine is injective on option A intervals. Other intervals repeat values.
For inverse sine, the sine function must remain one-one on the chosen interval. On both intervals in option A, sine changes monotonically without repeating values. Intervals in other options contain repeated sine outputs or incomplete ranges. Therefore only option A provides valid bijective branches.
- Option B → Sine repeats values on both intervals.
- Option C → Intervals contain symmetry causing repeated outputs.
- Option D → First interval does not cover full range [-1,1].
Used: Elimination
Application:
- Reject intervals where sine repeats outputs.
Final Logic:
- Bijective intervals must avoid repeated sine values.
"No repetition means valid inverse."
4 Which of the following analytical statements is mathematically INCORRECT concerning the principal branch of sin⁻¹?
Principal branch is [-π/2,π/2]. Cosine stays nonnegative there. Hence option A is false.
The principal branch of sin⁻¹x is: [-π/2,π/2]. In this interval, cosine values are always nonnegative. Therefore option A is incorrect. Statements B, C, and D are correct because the branch covers quadrants I and IV, spans length π, and remains increasing and continuous.
- Option B → Principal branch indeed lies in quadrants I and IV.
- Option C → Interval length equals π radians exactly.
- Option D → sin⁻¹x is continuous and strictly increasing.
Used: Elimination
Application:
- Check cosine sign behaviour in the principal branch.
Final Logic:
- Cosine never becomes negative on [-π/2,π/2].
"Cos positive in principal sine branch."
5 An angle y is analytically mapped from the expression sin⁻¹(√3/2). What is the exact fractional numerical value of this mapping interval's principal output in radians?
sin(π/3)=√3/2 π/3 lies in principal branch. Hence inverse value equals π/3.
The principal value of inverse sine lies in: [-π/2,π/2]. Since: sin(π/3)=√3/2, the principal output becomes: sin⁻¹(√3/2)=π/3. Hence option B is correct. Other angles produce different sine values.
- Option A → sin(π/6)=1/2.
- Option C → sin(π/4)=1/√2.
- Option D → sin(π/2)=1.
Used: Substitution
Application:
- Recall the exact angle corresponding to √3/2.
Final Logic:
- Principal angle with sine √3/2 is π/3.
"√3/2 belongs to 60°."
6 In the standard (x, y) Cartesian plane, the entire area strictly enclosed by the curve y = sin⁻¹x, the vertical y-axis, and the horizontal lines y = -π/2 and y = π/2 is bounded horizontally on its extremes precisely at:
Domain of sin⁻¹x is [-1,1]. Horizontal bounds come from domain. Hence extremes are x=−1 and 1.
The graph of y=sin⁻¹x exists only for: x∈[-1,1]. Thus the horizontal extent of the enclosed region is bounded by: x=−1 and x=1. Hence option B is correct. Other options confuse x-bounds with y-values or angle limits.
- Option A → These are angle values, not x-coordinates.
- Option C → Excludes half the graph region.
- Option D → Represents vertical limits instead of horizontal bounds.
Used: Dimensional/Unit Analysis
Application:
- Identify whether the question asks about horizontal or vertical limits.
Final Logic:
- Horizontal graph bounds come from the function domain.
"Domain controls left-right spread."
7 A processor computes y = sin(sin⁻¹x) for all inputs from -1 to 1. Because this relationship evaluates to y = x, what is the exact moving average of any two symmetrically opposed domain values (x and -x)?
sin(sin⁻¹x)=x Average of x and −x is zero. Symmetry cancels values exactly.
Using the identity: sin(sin⁻¹x)=x, the outputs become x and −x for symmetric inputs. Their average is: (x+(−x))/2=0. Hence option D is correct. Symmetric opposite values always cancel perfectly around the origin.
- Option A → Represents only one value, not the average.
- Option B → Same mistake with negative value only.
- Option C → Opposite values never average to 1 generally.
Used: Substitution
Application:
- Simplify the inverse identity before averaging.
Final Logic:
- Opposite symmetric values always average to zero.
"Opposites cancel instantly."
8 A continuous variable x is chosen completely uniformly from the interval [0, 2π]. What is the exact mathematical probability that the property sin⁻¹(sin x) = x evaluates as true?
Identity works only in principal branch. Valid interval inside [0,2π] is [0,π/2]. Probability becomes 1/4.
The identity: sin⁻¹(sin x)=x holds only for: x∈[-π/2,π/2]. Inside [0,2π], this reduces to [0,π/2], whose length is π/2. Total interval length is 2π. Thus probability: (π/2)/(2π)=1/4. Hence option D is correct.
- Option A → Identity fails outside principal branch.
- Option B → Overestimates valid interval length.
- Option C → Identity is true on part of the interval.
Used: Dimensional/Unit Analysis
Application:
- Use interval length ratio for continuous probability.
Final Logic:
- Valid branch length divided by total length equals 1/4.
"Only first quadrant survives."
9 A spatial vector transformation T strictly swaps the components of any vector (x,y) to (y,x). If T is applied to every coordinate vector making up the locus of y = sin x strictly where x ∈ [-π/2, π/2], the resulting new vector locus defines:
Inverse graphs swap coordinates. Reflection occurs along y=x. Resulting graph becomes inverse sine.
Swapping coordinates transforms the graph of a function into the graph of its inverse. Restricting sine to: [-π/2,π/2] ensures invertibility. Therefore the transformed locus becomes: y=sin⁻¹x. Hence option A is correct. Other options confuse reciprocal and inverse notation.
- Option B → Coordinate swapping does not create cosine inverse.
- Option C → Reciprocal sine differs from inverse sine.
- Option D → This is equivalent relation form but not standard graph equation.
Used: Contextual/Tonal Matching
Application:
- Use graph reflection property of inverse functions.
Final Logic:
- Coordinate interchange generates inverse-function graph.
"Swap coordinates to get inverse."
10 The region bounded by y = sin x (for x ∈ [0, π/2]), the y-axis, and y = 1 has an exact geometric area of (π/2 - 1). By utilizing the reflection along y = x, the integral ∫sin⁻¹x dx from 0 to 1 directly corresponds to this area. What is its numerical value?
Reflection preserves enclosed area. Inverse graph area equals original reflected area. Integral value becomes π/2−1.
Using reflection symmetry between y=sin x and y=sin⁻¹x about y=x, the enclosed areas remain equal. The known area bounded by y=sin x on [0,π/2] equals: π/2−1. Therefore: ∫₀¹ sin⁻¹x dx = π/2−1. Hence option C is correct.
- Option A → Ignores geometric area relation entirely.
- Option B → Represents interval length only, not enclosed area.
- Option D → Gives negative area, impossible geometrically.
Used: Contextual/Tonal Matching
Application:
- Use inverse-function reflection area property.
Final Logic:
- Reflected regions preserve identical area.
"Mirror areas stay equal."
11 Because y = sin⁻¹x behaves as a strictly increasing function on the sub-interval, what must identically be the mathematical sign of the definite integral of its derivative over this exact interval?
Increasing functions have positive derivatives. Integral of positive quantity stays positive. Hence result is positive.
The function y = sin⁻¹x is strictly increasing on its domain (-1,1). Therefore its derivative: 1/√(1−x²) remains positive throughout the interval. The definite integral of a positive function over any nonzero interval is positive. Hence option B is correct.
- Option A → Negative sign would imply decreasing behaviour.
- Option C → Positive derivative cannot integrate to zero on nonzero interval.
- Option D → Derivative exists and is integrable inside the interval.
Used: Contextual/Tonal Matching
Application:
- Relate increasing behaviour directly to derivative sign.
Final Logic:
- Increasing functions have positive derivative integrals.
"Increasing means positive slope."
12 Assertion (A): The mathematical evaluation of sin⁻¹(2) strictly equals π/2.
Reason (R): The defined domain limits of the sin⁻¹x function strictly exclude any numerical values greater than 1.
sin⁻¹x exists only on [-1,1]. 2 lies outside the domain. Therefore assertion is false.
The inverse sine function is defined only for: x∈[-1,1]. Since 2 lies outside this domain, sin⁻¹(2) has no real value. Therefore the Assertion is false. The Reason correctly states the domain restriction, making it true. Hence option D is correct.
- Option A → Reason is mathematically correct.
- Option B → Assertion is false, not true.
- Option C → Assertion itself is invalid, so explanation fails.
Used: Elimination
Application:
- Verify the allowed domain before evaluating inverse sine.
Final Logic:
- Inputs greater than 1 are invalid for sin⁻¹x.
"Beyond ±1, inverse sine fails."
13 Arrange the following inverse cosine evaluations strictly in descending order of their numerical radian results:
1. cos⁻¹(0)
2. cos⁻¹(-1)
3. cos⁻¹(1)
4. cos⁻¹(-1/2)
cos⁻¹(−1)=π cos⁻¹(−1/2)=2π/3 cos⁻¹(0)=π/2, cos⁻¹(1)=0
Using principal values: cos⁻¹(−1)=π, cos⁻¹(−1/2)=2π/3, cos⁻¹(0)=π/2, cos⁻¹(1)=0. Descending order becomes: π > 2π/3 > π/2 > 0. Thus the correct arrangement is: 2,4,1,3. Hence option A is correct.
- Option B → Places π/2 above π incorrectly.
- Option C → Reverses first two largest values.
- Option D → Starts with smallest value instead of largest.
Used: Substitution
Application:
- Evaluate each inverse cosine value individually.
Final Logic:
- Arrange evaluated angles from greatest to least.
"−1 gives biggest cosine inverse."
14 The exact mathematical solution to the equation cos⁻¹x = 2π/3 falls validly within the principal range [0, π]. What is the specific real value of x?
Apply cosine to both sides. cos(2π/3)=−1/2. Therefore x=−1/2.
Given: cos⁻¹x = 2π/3, apply cosine to both sides: x = cos(2π/3). Since: cos(2π/3)=−1/2, the required value becomes: x=−1/2. Hence option C is correct.
- Option A → cos(π/3)=1/2, not 2π/3.
- Option B → Corresponds to cosine π/6.
- Option D → Gives cosine value for 5π/6.
Used: Substitution
Application:
- Use direct inverse-function cancellation.
Final Logic:
- Applying cosine gives x=cos(2π/3).
"120° gives −1/2."
15 If the expression cos⁻¹x is analyzed strictly in an alternative, valid branch such as [π, 2π], the corresponding function behavior on this domain is:
Valid inverse branch requires bijection. Restricted cosine becomes one-one. Therefore inverse exists uniquely.
An inverse function exists only when the original function becomes bijective on the chosen interval. Restricting cosine to a valid branch such as [π,2π] allows unique inverse mapping over an appropriate range. Therefore the function behaves bijectively, making option B correct.
- Option A → Cosine is not strictly increasing throughout this interval.
- Option C → Valid restricted branches remain mathematically defined.
- Option D → Cosine clearly changes values over the interval.
Used: Contextual/Tonal Matching
Application:
- Focus on the condition required for inverse existence.
Final Logic:
- Inverse branches must always be bijective.
"Valid branch means bijection."
16 By examining the analytical graph of y = cos⁻¹x, the specific planar coordinate point where the curve intersects the horizontal x-axis is:
x-axis means y=0. cos⁻¹x=0 implies x=1. Intersection point becomes (1,0).
The graph intersects the x-axis where: y=0. So: cos⁻¹x=0. Applying cosine: x=cos0=1. Therefore the intersection point is: (1,0). Hence option D is correct.
- Option A → Lies on graph but not x-axis.
- Option B → Gives y-value π instead of 0.
- Option C → cos⁻¹(0)=π/2, not 0.
Used: Substitution
Application:
- Set y=0 and solve inverse equation directly.
Final Logic:
- Only x=1 makes cos⁻¹x equal zero.
"Cos inverse touches x-axis at 1."
17 When analytically comparing sin⁻¹x and cos⁻¹x, evaluating the expression (sin⁻¹x + cos⁻¹x) for any value of x strictly confined within [-1, 1] yields a universal constant. This constant is:
Standard inverse identity applies. Sum remains constant always. Constant equals π/2.
A standard inverse trigonometric identity states: sin⁻¹x + cos⁻¹x = π/2 for every: x∈[-1,1]. Therefore the expression always evaluates to the constant π/2. Hence option A is correct.
- Option B → Too large for the standard identity.
- Option C → Sum never becomes zero generally.
- Option D → Incorrect negative constant value.
Used: Substitution
Application:
- Recall the standard NCERT inverse identity.
Final Logic:
- Inverse sine and cosine always complement to π/2.
"Sine inverse plus cosine inverse equals 90°."
18 The identical domain similarity [-1, 1] necessary for defining both the inverse sine and inverse cosine mathematically originates from the fundamental fact that:
Inverse domain equals original range. Sine and cosine ranges are [-1,1]. Therefore inverse domains match.
For inverse functions, the domain equals the range of the original function. Since both sine and cosine have range: [-1,1], their inverses sin⁻¹x and cos⁻¹x also possess domain: [-1,1]. Hence option B is correct.
- Option A → Oddness does not determine inverse domains.
- Option C → Sine and cosine are not reciprocals.
- Option D → Graph intersections do not define domains.
Used: Contextual/Tonal Matching
Application:
- Use inverse-function relationship between domain and range.
Final Logic:
- Original function range becomes inverse domain.
"Inverse domain comes from original range."
19
sin⁻¹x is an odd function. Odd functions satisfy f(−x)=−f(x). Hence required relation follows.
The inverse sine function is odd because its graph is symmetric about the origin. Therefore: sin⁻¹(−x)=−sin⁻¹x. This property holds for all x in the domain [-1,1]. Hence option C is correct.
- Option A → Relation belongs to cosine-type identities.
- Option B → Would imply even symmetry, which is false.
- Option D → Inverse cosine is a different function entirely.
Used: Contextual/Tonal Matching
Application:
- Identify symmetry type of inverse sine graph.
Final Logic:
- Odd symmetry gives f(−x)=−f(x).
"Inverse sine is odd."
20
Inverse swaps x and y coordinates. Original function reverses the relation. Restricted domain ensures uniqueness.
If: y=f⁻¹(x), then by definition: f(y)=x. For inverse functions to exist uniquely, y must belong to the restricted domain where the original function is one-one. Therefore option D correctly expresses the reflection and inverse relationship.
- Option A → Original function domain cannot remain unrestricted.
- Option B → Restriction to positive y-values is unnecessary.
- Option C → Relation incorrectly keeps original coordinate order.
Used: Contextual/Tonal Matching
Application:
- Use the defining property of inverse functions carefully.
Final Logic:
- Inverse relation always satisfies f(y)=x.
"Inverse swaps input and output."
