Mathematics · Indefinite Integration

JEE Main 2026 — 22 January, Morning Shift — Question 22

If ∫(sin⁡x)−112(cos⁡x)−52dx=\int(\sin \mathrm{x})^{\frac{-11}{2}}(\cos \mathrm{x})^{\frac{-5}{2}} \mathrm{dx}= −p1q1(cot⁡x)92−p2q2(cot⁡x)52−p3q3(cot⁡x)12+p4q4(cot⁡x)−32+C-\frac{\mathrm{p}_{1}}{\mathrm{q}_{1}}(\cot \mathrm{x})^{\frac{9}{2}}-\frac{\mathrm{p}_{2}}{\mathrm{q}_{2}}(\cot \mathrm{x})^{\frac{5}{2}}-\frac{\mathrm{p}_{3}}{\mathrm{q}_{3}}(\cot \mathrm{x})^{\frac{1}{2}}+\frac{\mathrm{p}_{4}}{\mathrm{q}_{4}}(\cot \mathrm{x})^{\frac{-3}{2}}+\mathrm{C}, where pip_{i} and qiq_{i} are positive integers with gcd⁡(pi,qi)=1\operatorname{gcd}\left(p_{i}, q_{i}\right) =1 for i=1,2,3,4\mathrm{i}=1,2,3,4 and C is the constant of integration, then 15p1p2p3p4q1q2q3q4\frac{15 p_{1} p_{2} p_{3} p_{4}}{q_{1} q_{2} q_{3} q_{4}} is equal to ____\_\_\_\_ .

Answer: 16

Numerical answer — enter this value.

Step-by-step solution

∫(tan⁡x)−1/2⋅sec⁡8xdx\quad \int(\tan \mathrm{x})^{-1 / 2} \cdot \sec ^{8} \mathrm{x} \mathrm{dx}

=∫(tan⁡x)−11/2(1+tan⁡2x)3sec⁡2xdx=\int(\tan \mathrm{x})^{-11 / 2}\left(1+\tan ^{2} \mathrm{x}\right) 3 \sec ^{2} \mathrm{xdx}

Put tan⁡x=t\tan \mathrm{x}=\mathrm{t}

⇒∫t−11/2(1+t2)3dx=∫t−11/2(1+t6+3t2+3)dt\Rightarrow \int \mathrm{t}^{-11 / 2}\left(1+\mathrm{t}^{2}\right)^{3} \mathrm{dx}=\int \mathrm{t}^{-11 / 2}\left(1+\mathrm{t}^{6}+3 \mathrm{t}^{2}+3\right) \mathrm{dt}

=∫(t−11/2+t1/2+3.t−7/2+3.t−3/2)dt=\int\left(\mathrm{t}^{-11 / 2}+\mathrm{t}^{1 / 2}+3 . \mathrm{t}^{-7 / 2}+3 . \mathrm{t}^{-3 / 2}\right) \mathrm{dt} =−29(cot⁡x)9/2−65(cot⁡)5/2−6(cot⁡x)1/2+23(cot⁡x)−3/2+C=-\frac{2}{9}(\cot \mathrm{x})^{9 / 2}-\frac{6}{5}(\cot )^{5 / 2}-6(\cot \mathrm{x})^{1 / 2}+\frac{2}{3}(\cot \mathrm{x})^{-3 / 2}+\mathrm{C}

⇒p1=2,p2=6,p3=6,p4=2\Rightarrow \mathrm{p}_{1}=2, \mathrm{p}_{2}=6, \mathrm{p}_{3}=6, \mathrm{p}_{4}=2

q1=9,q2=5,q3=1,q4=3\mathrm{q}_{1}=9, \mathrm{q}_{2}=5, \mathrm{q}_{3}=1, \mathrm{q}_{4}=3

15p1p2p3p4q1q2q3q4=15⋅2⋅6⋅6⋅29⋅5⋅1⋅3=16\frac{15 p_{1} p_{2} p_{3} p_{4}}{q_{1} q_{2} q_{3} q_{4}}=\frac{15 \cdot 2 \cdot 6 \cdot 6 \cdot 2}{9 \cdot 5 \cdot 1 \cdot 3}=16

Answer key and solution verified before publishing.

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Exam
JEE Main 2026
Subject
Mathematics
Chapter
Indefinite Integration
Topic
Methods of Indefinite Integration