Question
Question: \[\int_{}^{}{\sin^{–1}(3x–4x^{3})dx =}\]...
∫sin–1(3x–4x3)dx=
A
x sin–1x + 1–x2 + c
B
x sin–1x – 1–x2 + c
C
2[x sin–1x +1–x2] + c
D
3[x sin–1x +1–x2] + c
Answer
3$$x sin–1x +1–x2$$ + c
Explanation
Solution
Put x = sinq
dx = cosq dq
\ ∫sin−1(3sinq – 4 sin3q) cosq dq
= ∫sin−1 (sin 3q) . cos dq = 3∫θ.cosθ.dθ
= 3 [q∫cosθdθ–∫{dθd(θ).∫cosθdθ}dθ]
= 3 [θsinθ–∫sinθdθ] = 3[q sin q + cosq] + c
= 3[x sin–1x + 1–x2] + c