Mathematics

# Solve :$\int cos^3x . dx$

##### SOLUTION
$\displaystyle \int cos^{3}xdx$
we know that
$\displaystyle cos^{3}x = 4cos^{3}x-3cosx$
$\dfrac{cos3x+3cosx}{4} = cos^{3}x$
put the value of $cos^{3}x$
$\displaystyle = \int \frac{cos3x+3cox}{4}dx$
$\displaystyle = \frac{1}{4}\int (cos3x+3cosx)dx$
$\displaystyle = \frac{1}{4}[\frac{sin3x}{3}+3sinx]+c$

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Subjective Medium Published on 17th 09, 2020
Questions 203525
Subjects 9
Chapters 126
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