# Please solve the question in the attachment.... ....... ..... ...........

Himanshu
14 Points
3 years ago

Using the idendity
$\sin(15x/2)=(3sin(5x/2)-4sin^{3}(5x/2))$---eq1
$\cos8x-\cos7x/1+2cox5x=-2sin(15x/2)(sinx/2)/1+2(1-2sin^{2}x)$
now using eq1 in the above equation$=-2\sin(5x/2)(3-4sin^{2}(5x/2))six(x/2)/(3-4sin^{2}(5x/2))$
on solving the expression
$=-2\sin(5x/2)sin(x/2)=cos2x-cos3x$
now performing the integral
$=\int cos2x-cos3x$
by using the formula for integration of cosine function
$\sin2x/2-sin3x/3$+$c$ is rhe answer
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