CUET UG Mathematics Booster Test 1 - Advanced Applications of Inverse Trigonometric Functions
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QUESTION 1 OF 20
Assertion (A): sec⁻¹(2) exists and its principal value is π/3.
Reason (R): The domain of sec⁻¹x is (-∞,-1] ∪ [1,∞), and its principal value lies in [0,π], excluding π/2.
QUESTION 2 OF 20
A force vector makes an angle θ such that
cot⁻¹(1)=θ.
Find the principal value of θ.
QUESTION 3 OF 20
The domain of sin⁻¹x is [-1,1]. A value is chosen uniformly at random from this domain.
What is the probability that the principal value lies in (0,π/2)?
QUESTION 4 OF 20
Evaluate:
tan(sin⁻¹(1/2))
QUESTION 5 OF 20
Arrange in ascending order:
1. sin(sin⁻¹0.2)
2. sin(sin⁻¹0.5)
3. sin(sin⁻¹0.8)
4. sin(sin⁻¹0.3)
QUESTION 6 OF 20
The integral calculation of a planar region involving inverse trigonometric functions requires using their principal value ranges. What is the principal value range of the function sin⁻¹x?
QUESTION 7 OF 20
Which of the following intervals are NOT standard principal value branches for inverse trigonometric functions?
1. [-π/2,π/2]
2. [0,π]
3. (-π,π)
4. [0,2π]
QUESTION 8 OF 20
Match each trigonometric function with the domain restriction required to make it bijective (for defining its inverse):
| List 1 | List 2 |
|---|---|
| 1. Sine | a. (0, π) |
| 2. Cosine | b. [−π/2, π/2] |
| 3. Tangent | c. (−π/2, π/2) |
| 4. Cotangent | d. (0, π) |
QUESTION 9 OF 20
Consider the equation:
sinx/(1-cosx)=tan(x/2)
Which of the following statements is INCORRECT?
QUESTION 10 OF 20
Consider the relation:
y = tan⁻¹x
What are the horizontal asymptotes of this graph?
QUESTION 11 OF 20
Given the angles sin⁻¹(1/2), cos⁻¹(1/2), and tan⁻¹(1), find their mean value.
QUESTION 12 OF 20
Evaluate the area represented by:
∫₀¹ 1/√(1-x²) dx
QUESTION 13 OF 20
The domain of inverse trigonometric functions collectively spans:
QUESTION 14 OF 20
What is the principal value branch of cos⁻¹x?
QUESTION 15 OF 20
Why must we define principal value branches for inverse trigonometric functions?
QUESTION 16 OF 20
Evaluate using principal value branches:
sin⁻¹(1/2)+cos⁻¹(1/2)
QUESTION 17 OF 20
QUESTION 18 OF 20
1. Bhaskara II
2. Aryabhata
3. Brahmagupta
4. Bhaskara I
QUESTION 19 OF 20
Aryabhata is historically recorded to have made his major mathematical contributions around which year?
QUESTION 20 OF 20
The 16th-century Malayalam mathematical work Yuktibhasa contains a detailed proof for the infinite series expansion of:
Test Complete!
Answer Review
1 Assertion (A): sec⁻¹(2) exists and its principal value is π/3.
Reason (R): The domain of sec⁻¹x is (-∞,-1] ∪ [1,∞), and its principal value lies in [0,π], excluding π/2.
sec⁻¹x exists for |x| ≥ 1. sec(π/3)=2. Principal range excludes π/2.
The function sec⁻¹x is defined for x ≤ -1 or x ≥ 1. Since 2 belongs to this domain, sec⁻¹(2) exists. Also, sec(π/3)=2 and π/3 lies in the principal value branch [0,π] excluding π/2. Therefore both Assertion and Reason are true, and the Reason correctly explains the Assertion.
- Option A → Both statements are mathematically correct.
- Option B → The reason is true because it correctly states domain and principal range.
- Option D → Assertion is also true since sec⁻¹(2)=π/3.
Used: Substitution
Application:
- Substitute θ=π/3 into secθ and verify domain conditions.
Final Logic:
- sec(π/3)=2 and π/3 belongs to the principal branch.
"sec⁻¹ accepts numbers outside ±1."
2 A force vector makes an angle θ such that
cot⁻¹(1)=θ.
Find the principal value of θ.
cot(π/4)=1. Principal range is (0,π). Hence θ=π/4.
The principal value branch of cot⁻¹x lies in (0,π). Since cot(π/4)=1, the principal value satisfying cot⁻¹(1)=θ is π/4. The angle π/4 lies within the valid principal range, making option A correct.
- Option B → cot(π/2)=0, not 1.
- Option C → cot(3π/4)=-1, not 1.
- Option D → cot(0) is undefined.
Used: Substitution
Application:
- Use standard trigonometric values inside principal range.
Final Logic:
- cot(π/4)=1 uniquely determines θ.
"cot 45° equals 1."
3 The domain of sin⁻¹x is [-1,1]. A value is chosen uniformly at random from this domain.
What is the probability that the principal value lies in (0,π/2)?
Positive x gives positive sin⁻¹x. Half interval is positive. Probability equals 1/2.
The principal range of sin⁻¹x is [-π/2,π/2]. The output lies in (0,π/2) whenever x∈(0,1]. From the domain [-1,1], exactly half the interval corresponds to positive x-values. Hence the probability is 1/2.
- Option A → Underestimates favorable region.
- Option C → Overestimates positive interval size.
- Option D → Duplicate numerical value appears, but B is intended correct choice.
Used: Contextual/Tonal Matching
Application:
- Relate positivity of sin⁻¹x directly to positivity of x.
Final Logic:
- Positive half of the domain gives positive principal values.
"sin⁻¹ keeps the sign of x."
4 Evaluate:
tan(sin⁻¹(1/2))
sin⁻¹(1/2)=π/6. tan(π/6)=1/√3. Standard angle evaluation.
First evaluate: sin⁻¹(1/2)=π/6 because π/6 lies in the principal range of sin⁻¹x. Now: tan(π/6)=1/√3. Hence the expression equals 1/√3, making option A correct.
- Option B → Duplicate of option A.
- Option C → tan(π/3)=√3, unrelated here.
- Option D → tan(π/4)=1, not π/6.
Used: Substitution
Application:
- Convert inverse trig value into standard angle.
Final Logic:
- sin⁻¹(1/2)=π/6 leads directly to tan(π/6).
"Half gives 30°, tan30°=1/√3."
5 Arrange in ascending order:
1. sin(sin⁻¹0.2)
2. sin(sin⁻¹0.5)
3. sin(sin⁻¹0.8)
4. sin(sin⁻¹0.3)
sin(sin⁻¹x)=x. Values become 0.2, 0.5, 0.8, 0.3. Arrange numerically.
Using the identity: sin(sin⁻¹x)=x. The values become: 0.2, 0.5, 0.8, 0.3. Ascending order: 0.2 < 0.3 < 0.5 < 0.8. Therefore: 1,4,2,3. Hence option B is correct.
- Option A → Places 0.8 before 0.3 incorrectly.
- Option C → Starts with the largest value first.
- Option D → Entire sequence is not ascending.
Used: Substitution
Application:
- Reduce composite functions to direct numerical values.
Final Logic:
- Arrange simplified values in increasing order.
"sin and sin⁻¹ cancel."
6 The integral calculation of a planar region involving inverse trigonometric functions requires using their principal value ranges. What is the principal value range of the function sin⁻¹x?
sin⁻¹x requires bijective sine branch. Standard branch is symmetric. Endpoints included.
To define inverse sine uniquely, the sine function is restricted to: [-π/2,π/2]. Within this interval sine is one-one and onto [-1,1]. Hence the principal value range of sin⁻¹x is exactly [-π/2,π/2], making option D correct.
- Option A → Too wide; sine repeats values there.
- Option B → Corresponds to cos⁻¹x range.
- Option C → Incorrect because endpoints ±π/2 are included.
Used: Contextual/Tonal Matching
Application:
- Recall the standard principal branch used for inverse sine.
Final Logic:
- Inverse sine uses the restricted interval [-π/2,π/2].
"sin⁻¹ lives between ±90°."
7 Which of the following intervals are NOT standard principal value branches for inverse trigonometric functions?
1. [-π/2,π/2]
2. [0,π]
3. (-π,π)
4. [0,2π]
Standard branches include intervals 1 and 2. (-π,π) and [0,2π] are not standard. Hence 3 and 4 only.
Standard principal value branches are: [-π/2,π/2] for sin⁻¹x and tan⁻¹x, and [0,π] for cos⁻¹x. Intervals (-π,π) and [0,2π] are not standard principal branches because trigonometric functions are not one-one there. Therefore option D is correct. The provided answer A is incorrect.
- Option A → Incorrectly includes [0,π], which is a valid standard branch.
- Option B → Both intervals listed are standard principal branches.
- Option C → Incorrectly marks [-π/2,π/2] as non-standard.
Used: Elimination
Application:
- Identify intervals officially used in NCERT principal branches.
Final Logic:
- Only intervals 3 and 4 fail as standard branches.
"Principal branches avoid repeated values."
8 Match each trigonometric function with the domain restriction required to make it bijective (for defining its inverse):
| List 1 | List 2 |
|---|---|
| 1. Sine | a. (0, π) |
| 2. Cosine | b. [−π/2, π/2] |
| 3. Tangent | c. (−π/2, π/2) |
| 4. Cotangent | d. (0, π) |
Sine uses [-π/2,π/2]. Cosine and cotangent use (0,π). Tangent uses (-π/2,π/2).
Standard bijective restrictions are: Sine → [-π/2,π/2] Cosine → [0,π] or equivalent convention near (0,π) Tangent → (-π/2,π/2) Cotangent → (0,π). Thus matching corresponds best with option B. The provided answer C is incorrect because cosine does not use (-π/2,π/2).
- Option A → Incorrectly assigns sine to (0,π).
- Option C → Gives cosine wrong interval.
- Option D → Assigns sine incorrect tangent-style interval.
Used: Option Grouping
Application:
- Recall standard restricted intervals used for each inverse function.
Final Logic:
- Only option B correctly matches all principal restrictions.
"sin symmetric, tan open, cos and cot positive π interval."
9 Consider the equation:
sinx/(1-cosx)=tan(x/2)
Which of the following statements is INCORRECT?
Denominator cannot be zero. cosx=1 causes undefined form. Hence not valid for all real x.
Using half-angle identities: sinx/(1-cosx)=cot(x/2), while related identities involve tan(x/2). The expression becomes undefined whenever: 1-cosx=0 ⇒ cosx=1. Thus it cannot hold for all real x. Hence option D is the incorrect statement.
- Option A → x=π/2 gives valid finite values.
- Option B → Such relations arise from standard trigonometric identities.
- Option C → Correct restriction avoids zero denominator.
Used: Extreme Word Filter
Application:
- The phrase "all real x" often signals invalid overgeneralization.
Final Logic:
- Expressions with denominators always need restrictions.
"Denominator zero destroys identity."
10 Consider the relation:
y = tan⁻¹x
What are the horizontal asymptotes of this graph?
tan⁻¹x principal range is bounded. As x→±∞, outputs approach ±π/2. Hence horizontal asymptotes exist.
For the inverse tangent function: y=tan⁻¹x, as: x→∞, y→π/2 and x→−∞, y→−π/2. Therefore the graph approaches the horizontal lines: y=±π/2. Hence option B is correct.
- Option A → Corresponds to cot⁻¹x-type limits.
- Option C → tan⁻¹x never approaches ±π.
- Option D → Horizontal asymptotes clearly exist.
Used: Contextual/Tonal Matching
Application:
- Recall standard graph behavior of inverse tangent.
Final Logic:
- tan⁻¹x is bounded between ±π/2.
"tan⁻¹ hugs ±90°."
11 Given the angles sin⁻¹(1/2), cos⁻¹(1/2), and tan⁻¹(1), find their mean value.
sin⁻¹(1/2)=π/6. cos⁻¹(1/2)=π/3 and tan⁻¹(1)=π/4. Average equals π/4.
The principal values are: sin⁻¹(1/2)=π/6, cos⁻¹(1/2)=π/3, tan⁻¹(1)=π/4. Their mean is: (π/6 + π/3 + π/4)/3 = (2π+4π+3π)/12 ÷3 = 9π/12 ÷3 = 3π/4 ÷3 = π/4. Hence option A is correct. The provided explanation incorrectly simplified to π/3.
- Option B → Arithmetic simplification error.
- Option C → Duplicate incorrect option.
- Option D → Too large compared to actual average.
Used: Substitution
Application:
- Replace each inverse trigonometric value with its standard angle.
Final Logic:
- Correct averaging gives π/4.
"30°, 60°, 45° average to 45°."
12 Evaluate the area represented by:
∫₀¹ 1/√(1-x²) dx
Integral equals sin⁻¹x. Evaluate from 0 to 1. Result is π/2.
Using the standard integration formula: ∫ dx/√(1-x²)=sin⁻¹x + C. Evaluating between 0 and 1: sin⁻¹(1)-sin⁻¹(0) = π/2 - 0 = π/2. Therefore option A is correct.
- Option B → Double the correct value.
- Option C → Ignores inverse trigonometric evaluation.
- Option D → Integral over positive interval cannot vanish.
Used: Substitution
Application:
- Recognize standard inverse trigonometric integral form.
Final Logic:
- Boundary substitution directly yields π/2.
"1/√(1-x²) → sin⁻¹x."
13 The domain of inverse trigonometric functions collectively spans:
Different inverse functions have different domains. tan⁻¹x and cot⁻¹x accept all reals. Collectively domains cover R.
Inverse trigonometric functions do not share one common domain. Functions like tan⁻¹x and cot⁻¹x are defined for all real numbers, while sin⁻¹x and cos⁻¹x are restricted to [-1,1]. Hence, taken collectively, inverse trigonometric domains span all real numbers. Therefore option A is correct.
- Option B → Only for sin⁻¹x and cos⁻¹x.
- Option C → Represents principal range of cot⁻¹x or cos⁻¹x.
- Option D → Principal range, not collective domain.
Used: Option Grouping
Application:
- Compare domains of all inverse trigonometric functions together.
Final Logic:
- tan⁻¹x extends the collective domain to all reals.
"tan⁻¹ unlocks all real numbers."
14 What is the principal value branch of cos⁻¹x?
cos⁻¹x requires one-one cosine branch. Standard restriction is [0,π]. Endpoints included.
To define cos⁻¹x uniquely, cosine is restricted to [0,π], where it becomes bijective. Therefore the principal value branch of cos⁻¹x is [0,π]. This interval includes both endpoints and covers the entire range of cosine from 1 to -1.
- Option A → Principal branch of sin⁻¹x.
- Option B → Cosine repeats values in this interval.
- Option C → Too large; cosine not one-one there.
Used: Contextual/Tonal Matching
Application:
- Recall standard NCERT principal branch definitions.
Final Logic:
- cos⁻¹x always uses [0,π].
"Cos travels from 0° to 180°."
15 Why must we define principal value branches for inverse trigonometric functions?
Inverses require one-one mappings. Trigonometric functions are periodic. Restrictions create bijective branches.
Inverse functions exist only when the original function is one-one and onto. Trigonometric functions repeat values periodically over their natural domains, so they are not one-one. Hence principal value branches are defined by restricting domains appropriately. Therefore option B is correct.
- Option A → Differentiability is not the main reason.
- Option C → Probability has no role in branch definition.
- Option D → Mathematical necessity, not convention alone.
Used: Contextual/Tonal Matching
Application:
- Use the basic inverse-function condition of injectivity.
Final Logic:
- Periodic repetition prevents unrestricted inverses.
"No one-one, no inverse."
16 Evaluate using principal value branches:
sin⁻¹(1/2)+cos⁻¹(1/2)
sin⁻¹(1/2)=π/6. cos⁻¹(1/2)=π/3. Sum equals π/2.
Using principal values: sin⁻¹(1/2)=π/6 and cos⁻¹(1/2)=π/3. Adding: π/6 + π/3 = π/6 + 2π/6 = 3π/6 = π/2. Hence option C is correct. This also follows the identity: sin⁻¹x + cos⁻¹x = π/2.
- Option A → Only equals sin⁻¹(1/2).
- Option B → Only equals cos⁻¹(1/2).
- Option D → Sum is much smaller than π.
Used: Substitution
Application:
- Replace inverse values with standard angles.
Final Logic:
- Known identity gives π/2 immediately.
"sin⁻¹x + cos⁻¹x = 90°."
17
Passage compares Greek and Indian approaches. Greek method called clumsy. Indian system became preferred worldwide.
The passage explicitly states that the Greek approach to trigonometry was "clumsy." When the Indian approach became known, it was adopted worldwide because it was more effective and systematic. Hence option D directly matches the passage statement and is correct.
- Option A → Translation alone was not the reason stated.
- Option B → No European mandate is mentioned.
- Option C → Aryabhata did not enforce global adoption.
Used: Contextual/Tonal Matching
Application:
- Identify the exact textual reason given in the passage.
Final Logic:
- The passage directly attributes adoption to Greek inefficiency.
"Clumsy Greeks, smooth Indian method."
18
1. Bhaskara II
2. Aryabhata
3. Brahmagupta
4. Bhaskara I
Aryabhata: 476 A.D. Brahmagupta: 598 A.D. Bhaskara I: 600 A.D.; Bhaskara II: 1114 A.D.
Chronological order by year: Aryabhata (476 A.D.) → Brahmagupta (598 A.D.) → Bhaskara I (600 A.D.) → Bhaskara II (1114 A.D.). Thus the correct sequence is: 2,3,4,1. Hence option A is correct.
- Option B → Begins with latest mathematician first.
- Option C → Places Brahmagupta before Aryabhata incorrectly.
- Option D → Swaps Brahmagupta and Bhaskara I incorrectly.
Used: Arrange Chronologically
Application:
- Use historical years given in the passage.
Final Logic:
- Ascending year order determines sequence.
"Arya → Brahma → Bhaskara I → Bhaskara II."
19 Aryabhata is historically recorded to have made his major mathematical contributions around which year?
Aryabhata lived earliest among listed scholars. Passage explicitly gives 476 A.D. Historical fact-based question.
The passage directly states: "Aryabhata (476 A.D.)." Therefore his major mathematical contributions are associated with 476 A.D. Hence option C is correct.
- Option A → Corresponds to Brahmagupta.
- Option B → Corresponds to Bhaskara I.
- Option D → Corresponds to Bhaskara II.
Used: Elimination
Application:
- Match mathematicians with their historically associated years.
Final Logic:
- Only 476 A.D. belongs to Aryabhata.
"Aryabhata → 476."
20 The 16th-century Malayalam mathematical work Yuktibhasa contains a detailed proof for the infinite series expansion of:
Yuktibhasa discussed infinite series. Famous result includes arctangent expansion. Linked to Kerala School mathematics.
The Kerala School text Yuktibhasa is historically known for rigorous derivations of infinite series expansions, including: tan⁻¹x = x − x³/3 + x⁵/5 − ⋯ This series later became famous in calculus developments. Therefore option B is correct.
- Option A → Sine series is famous but not the highlighted result here.
- Option C → Exponential series belongs to later analysis developments.
- Option D → Cosine series is not the intended historical reference.
Used: Contextual/Tonal Matching
Application:
- Recall Kerala School contribution to inverse tangent series.
Final Logic:
- Yuktibhasa is strongly associated with arctangent expansion.
"Yuktibhasa → tan⁻¹ series."
