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Question

Question: \[\int_{}^{}{\sin^{–1}(3x–4x^{3})dx =}\]...

sin1(3x4x3)dx=\int_{}^{}{\sin^{–1}(3x–4x^{3})dx =}

A

x sin–1x + 1x2\sqrt{1–x^{2}} + c

B

x sin–1x – 1x2\sqrt{1–x^{2}} + c

C

2[x sin–1x +1x2\sqrt{1–x^{2}}] + c

D

3[x sin–1x +1x2\sqrt{1–x^{2}}] + c

Answer

3$$x sin–1x +1x2\sqrt{1–x^{2}}$$ + c

Explanation

Solution

Put x = sinq

dx = cosq dq

\ sin1\int \sin ^ { - 1 }(3sinq – 4 sin3q) cosq dq

= sin1\int \sin ^ { - 1 } (sin 3q) . cos dq = 3θ.cosθ.dθ3\int_{}^{}{\theta.\cos\theta.d\theta}

= 3 [qcosθdθ\int_{}^{}{\cos\theta d\theta}{ddθ(θ).cosθdθ}dθ]\int_{}^{}{\{\frac{d}{d\theta}(\theta).\int_{}^{}{\cos\theta d\theta\} d\theta}\rbrack}

= 3 [θsinθsinθdθ]\lbrack\theta\sin\theta –\int_{}^{}{\sin\theta d\theta\rbrack} = 3[q sin q + cosq] + c

= 3[x sin–1x + 1x2\sqrt{1–x^{2}}] + c