What is the integral of cos(x)*sin(2x) ?

The integral of cos(x)*sin(2x) is -2/3 cos^3(x)+C

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integral of cos(x)*sin(2x)

\int cos (x) \cdot sin (2 x) d x

- \frac{2}{3} cos^{3} (x) + C

Solution steps

\int cos (x) sin (2 x) d x

Rewrite using trig identities

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

Take the constant out:

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

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

Apply u-substitution

: \int - u^{2} d u

= 2 \cdot \int - u^{2} d u

Take the constant out:

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

= 2 (- \int u^{2} d u)

Apply the Power Rule

: \frac{u ^{3}}{3}

= 2 (- \frac{u ^{3}}{3})

Substitute back

u = cos (x)

= 2 (- \frac{cos ^{3} ( x )}{3})

Simplify

2 (- \frac{cos ^{3} ( x )}{3}) : - \frac{2}{3} cos^{3} (x)

= - \frac{2}{3} cos^{3} (x)

Add a constant to the solution

= - \frac{2}{3} cos^{3} (x) + C

\frac{\partial}{\partial x} (cos (2 x y))

3 x^{2} y d x + x^{3} d y = 0

\int_{0}^{2} e^{6 x} d x

\int - cos (5 x) d x

\frac{x ^{2} + x}{x ^{2} + 4 x}

What is the integral of cos(x)*sin(2x) ?
The integral of cos(x)*sin(2x) is -2/3 cos^3(x)+C