What is the integral of (cos(3x))/(sin(3x)) ?

The integral of (cos(3x))/(sin(3x)) is 1/3 ln|sin(3x)|+C

English

Español

Português

Français

Deutsch

Italiano

Русский

中文(简体)

한국어

日本語

Tiếng Việt

עברית

العربية

integral of (cos(3x))/(sin(3x))

\int \frac{cos ( 3 x )}{sin ( 3 x )} d x

\frac{1}{3} ln ∣ sin (3 x) ∣ + C

Solution steps

\int \frac{cos ( 3 x )}{sin ( 3 x )} d x

Apply u-substitution

= \int \frac{1}{3 u} d u

Take the constant out:

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

= \frac{1}{3} \cdot \int \frac{1}{u} d u

Use the common integral:

\int \frac{1}{u} d u = ln (∣ u ∣)

= \frac{1}{3} ln ∣ u ∣

Substitute back

u = sin (3 x)

= \frac{1}{3} ln ∣ sin (3 x) ∣

Add a constant to the solution

= \frac{1}{3} ln ∣ sin (3 x) ∣ + C

What is the integral of (cos(3x))/(sin(3x)) ?
The integral of (cos(3x))/(sin(3x)) is 1/3 ln|sin(3x)|+C