Sign in
12thPass logo
New chatPYQ LibraryDoubtsRank report
Sign in to see Recents

Your guest activity stays on this device

Sign in to save progress →
Sign in

Inverse Trigonometric Functions question

2024 · 9 Apr · Shift 2 · Q59
Guest · filters and generic practice availableBrowsing as a guest · PYQ filters and generic practice are available. Sign in only for personalised features and saved progress.
  1. PYQ Library
  2. /JEE Main
  3. /Mathematics
  4. /Inverse Trigonometric Functions
  5. /2024 · 9 Apr · Shift 2 · Q59

Inverse Trigonometric Functions question

2024 · 9 Apr · Shift 2 · Q59

JEE MainMathematicsInverse Trigonometric FunctionsNumerical+4 / −1
Let the inverse trigonometric functions take principal values. The number of real solutions of the equation 2sin⁡−1x+3cos⁡−1x=2π52 \sin ^{-1} x+3 \cos ^{-1} x=\frac{2 \pi}{5}2sin−1x+3cos−1x=52π​, is ‾\underline{\hspace{2cm}}​.
Numerical answer
View written solutionFree

Correct answer: 0

  1. Use the principal-value identity

For real x∈[−1,1]x \in [-1,1]x∈[−1,1], sin⁡−1x+cos⁡−1x=π2.\sin^{-1}x + \cos^{-1}x = \frac{\pi}{2}.sin−1x+cos−1x=2π​.

Let sin⁡−1x=y.\sin^{-1}x = y.sin−1x=y. Then cos⁡−1x=π2−y.\cos^{-1}x = \frac{\pi}{2} - y.cos−1x=2π​−y.

  1. Substitute into the given equation

Given 2sin⁡−1x+3cos⁡−1x=2π5,2\sin^{-1}x + 3\cos^{-1}x = \frac{2\pi}{5},2sin−1x+3cos−1x=52π​, so 2y+3(π2−y)=2π5.2y + 3\left(\frac{\pi}{2} - y\right) = \frac{2\pi}{5}.2y+3(2π​−y)=52π​.

Now simplify: 2y+3π2−3y=2π52y + \frac{3\pi}{2} - 3y = \frac{2\pi}{5}2y+23π​−3y=52π​ −y+3π2=2π5-y + \frac{3\pi}{2} = \frac{2\pi}{5}−y+23π​=52π​ y=3π2−2π5=15π−4π10=11π10.y = \frac{3\pi}{2} - \frac{2\pi}{5} = \frac{15\pi - 4\pi}{10} = \frac{11\pi}{10}.y=23π​−52π​=1015π−4π​=1011π​.

So we get sin⁡−1x=11π10.\sin^{-1}x = \frac{11\pi}{10}.sin−1x=1011π​.

  1. Check principal value range

The principal value range of sin⁡−1x\sin^{-1}xsin−1x is [−π2,π2].\left[-\frac{\pi}{2},\frac{\pi}{2}\right].[−2π​,2π​].

But 11π10>π2,\frac{11\pi}{10} > \frac{\pi}{2},1011π​>2π​, so this is impossible for any real xxx.

Hence, there is no real solution.

  1. Number of real solutions

Therefore, the number of real solutions is 0.0.0.

PreviousNext

More from Inverse Trigonometric Functions

  • Considering only the principal values of inverse trigonometric functions, the number of positive real values of x satisfying tan−1(x)+tan−1(2x)=4π​ is :2024 · MCQ
  • Let x=nm​ (m,n are co-prime natural numbers) be a solution of the equation cos(2sin−1x)=91​ and let α,β(α>β) be the roots of the equation mx2−nx−m+n=0. Then the…2024 · MCQ
  • For α,β,γeq0, if sin−1α+sin−1β+sin−1γ=π and (α+β+γ)(α−γ+β)=3αβ, then γ equals2024 · MCQ
  • If a=sin−1(sin(5)) and b=cos−1(cos(5)), then a2+b2 is equal to2024 · MCQ
  • Let S be the set of all solutions of the equation cos−1(2x)−2cos−1(1−x2​)=π,x∈[−21​,21​]. Then ∑x∈S​2sin−1(x2−1) is equal to :2023 · MCQ
  • Let S={x∈R:0<x<1 and 2tan−1(1+x1−x​)=cos−1(1+x21−x2​)}. If n(S) denotes the number of elements in S then :2023 · MCQ
  • If the domain of the function f(x)=sec−1(5x+32x​) is [α,β)U(γ,δ], then ∣3α+10(β+γ)+21δ∣ is equal to ​.2023 · Numerical
  • If S={x∈R:sin−1(x2+2x+2​x+1​)−sin−1(x2+1​x​)=4π​}, then ∑x∈s​(sin((x2+x+5)2π​)−cos((x2+x+5)π))…2023 · Numerical