What is the integral of 4(cos(x))^2 ?

The integral of 4(cos(x))^2 is 2x+sin(2x)+C

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integral of 4(cos(x))^2

\int 4 (cos (x))^{2} d x

2 x + sin (2 x) + C

Solution steps

\int 4 (cos (x))^{2} d x

Take the constant out:

\int a \cdot f (x) d x = a \cdot \int f (x) d x

= 4 \cdot \int (cos (x))^{2} d x

Simplify

= 4 \cdot \int cos^{2} (x) d x

Rewrite using trig identities

= 4 \cdot \int \frac{1 + cos ( 2 x )}{2} d x

Take the constant out:

\int a \cdot f (x) d x = a \cdot \int f (x) d x

= 4 \cdot \frac{1}{2} \cdot \int 1 + cos (2 x) d x

Apply the Sum Rule:

\int f (x) \pm g (x) d x = \int f (x) d x \pm \int g (x) d x

= 4 \cdot \frac{1}{2} (\int 1 d x + \int cos (2 x) d x)

\int 1 d x = x

\int cos (2 x) d x = \frac{1}{2} sin (2 x)

= 4 \cdot \frac{1}{2} (x + \frac{1}{2} sin (2 x))

Simplify

4 \cdot \frac{1}{2} (x + \frac{1}{2} sin (2 x)) : 2 x + sin (2 x)

= 2 x + sin (2 x)

Add a constant to the solution

= 2 x + sin (2 x) + C

What is the integral of 4(cos(x))^2 ?
The integral of 4(cos(x))^2 is 2x+sin(2x)+C