1.

Integrate sin^2 into log x by X​

Answer»

Solution:-

:    \implies\rm \int  \dfrac{ \sin^{2}  log  x }{x}  \: dx \\

:- USING substitution method

\rm \: let

\rm\to \: logx = t

:- differentiate on both side

\rm \to  \dfrac{1}{x}  dx= dt

Now take

:    \implies\rm \int  \dfrac{ \sin^{2}  log  x }{x}  \: dx \\

\rm : \implies \int  { \sin {}^{2} t} \:  dt \\

Now we can write

\rm \to1 - 2 \sin {}^{2} t =  \cos2t

\rm \to \: 1 -  \cos2t = 2 \sin {}^{2} t

\rm \to \sin {}^{2} t =  \dfrac{1 -  \cos2t}{2}

Now substitute the value of sin²t

\rm :  \implies \int \dfrac{1 -  \cos2t }{2} dt \\

Take 1/2 out side the integration because it is constant TERM

\rm  : \implies  \dfrac{1}{2} \int1 -  \cos2t \: dt \\

By integration we get

\rm :  \implies \:  \dfrac{1}{2}  \bigg(t -  \dfrac{1}{2}  \sin2t \bigg) + c

\rm :  \implies \dfrac{1}{2} t -  \dfrac{1}{4}  \sin2t + c

Now PUT the value of t

\rm  : \implies \dfrac{1}{2}  logx -  \dfrac{1}{4}  \sin2 logx + c

ANSWER

\rm  : \implies \dfrac{1}{2}  logx -  \dfrac{1}{4}  \sin2 logx + c



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