Mathematics · Inverse Trigonometric Functions

JEE Main 2026 — 21 January, Morning Shift — Question 1

If the domain of the function f(x)=cos⁡−1(2x−511−3x)+sin⁡−1(2x2−3x+1)f(x)=\cos ^{-1}\left(\frac{2 x-5}{11-3 x}\right)+\sin ^{-1}\left(2 x^{2}-3 x+1\right) is the interval [α,β][\alpha, \beta], then α+2β\alpha+2 \beta is equal to :

  1. Option A:

    11

  2. Option B:

    33

    Correct
  3. Option C:

    55

  4. Option D:

    22

Answer: B

Step-by-step solution

f(x)=cos⁡−1(2x−511−3x)+sin⁡−1(2x2−3x+1)f(x)=\cos ^{-1}\left(\frac{2 x-5}{11-3 x}\right)+\sin ^{-1}\left(2 x^{2}-3 x+1\right)

−1≤2x−511−3x≤1-1 \leq \frac{2 \mathrm{x}-5}{11-3 \mathrm{x}} \leq 1

−1≤2x2−3x+1≤1-1 \leq 2 \mathrm{x}^{2}-3 \mathrm{x}+1 \leq 1

2x2−3x+2≥0,2x2−3x≤02 \mathrm{x}^{2}-3 \mathrm{x}+2 \geq 0,2 \mathrm{x}^{2}-3 \mathrm{x} \leq 0

x∈[0,32]\begin{gathered} \mathrm{x} \in\left[0, \frac{3}{2}\right] \end{gathered} 2x−511−3x+1≥02x−5+11−3x11−3x≥0\begin{aligned} & \frac{2 x-5}{11-3 x}+1 \geq 0 & \frac{2 x-5+11-3 x}{11-3 x} \geq 0 \end{aligned} 5x−1611−3x≤0\frac{5 x-16}{11-3 x} \leq 0 6−x11−3x≥0\frac{6-x}{11-3 x} \geq 0 x∈(−∞,165]∪(113,∞)x \in\left(-\infty, \frac{16}{5}\right] \cup\left(\frac{11}{3}, \infty\right)

x∈(−∞,113)∪[6,∞)\mathrm{x} \in\left(-\infty, \frac{11}{3}\right) \cup[6, \infty)

intersection x∈(−∞,165]∪[6,∞)\begin{gathered} x \in\left(-\infty, \frac{16}{5}\right] \cup[6, \infty) \end{gathered}

Intersection of (i) & (ii) x∈[0,32]\mathrm{x} \in\left[0, \frac{3}{2}\right] α=0,β=32⇒α+2β=3\alpha=0, \beta=\frac{3}{2} \Rightarrow \alpha+2 \beta=3

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Answer key and solution verified before publishing.

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Exam
JEE Main 2026
Subject
Mathematics
Chapter
Inverse Trigonometric Functions
Topic
Equations, Inequations and Identitites involving ITFs
If the domain of the function f(x)=cos -1 (2 x-5/11-3 x )+sin -1 (2 x… | JEE Main 2026 PYQ with Solution · DhiX AI