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Question

Question: \[\int_{}^{}\left( \mathbf{\sin}^{\mathbf{4}}\mathbf{x}\mathbf{-}\mathbf{\cos}^{\mathbf{4}}\mathbf{x...

(sin4xcos4x)dx=\int_{}^{}\left( \mathbf{\sin}^{\mathbf{4}}\mathbf{x}\mathbf{-}\mathbf{\cos}^{\mathbf{4}}\mathbf{x} \right)\mathbf{dx =}

A

cos2x2+c- \frac{\cos 2x}{2} + c

B

sin2x2+c- \frac{\sin 2x}{2} + c

C

sin2x2+c\frac{\sin 2x}{2} + c

D

cos2x2+c\frac{\cos 2x}{2} + c

Answer

sin2x2+c- \frac{\sin 2x}{2} + c

Explanation

Solution

(sin4xcos4x)dx=(sin2xcos2x)(sin2x+cos2x)dx=(sin2xcos2x)dx=(cos2xsin2x)dx=cos2xdx\int_{}^{}{(\sin^{4}x - \cos^{4}x)dx} = \int_{}^{}{(\sin^{2}x - \cos^{2}x)(\sin^{2}x + \cos^{2}x)dx} = \int_{}^{}{(\sin^{2}x - \cos^{2}x)dx}\mathbf{= -}\int_{}^{}{\mathbf{(}\mathbf{\cos}^{\mathbf{2}}\mathbf{x}}\mathbf{-}\mathbf{\sin}^{\mathbf{2}}\mathbf{x}\mathbf{)dx = -}\int_{}^{}{\mathbf{\cos}\mathbf{2}\mathbf{xdx}} =sin2x2+C\mathbf{=}\frac{\mathbf{-}\mathbf{\sin}\mathbf{2}\mathbf{x}}{\mathbf{2}}\mathbf{+ C}