What is the integral of 9tan(x) ?

The integral of 9tan(x) is -9ln|cos(x)|+C

English

Español

Português

Français

Deutsch

Italiano

Русский

中文(简体)

한국어

日本語

Tiếng Việt

עברית

العربية

integral of 9tan(x)

\int 9 tan (x) d x

- 9 ln ∣ cos (x) ∣ + C

Solution steps

\int 9 tan (x) d x

Take the constant out:

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

= 9 \cdot \int tan (x) d x

Rewrite using trig identities

= 9 \cdot \int \frac{sin ( x )}{cos ( x )} d x

Apply u-substitution

= 9 \cdot \int - \frac{1}{u} d u

Take the constant out:

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

= 9 (- \int \frac{1}{u} d u)

Use the common integral:

\int \frac{1}{u} d u = ln (∣ u ∣)

= 9 (- ln ∣ u ∣)

Substitute back

u = cos (x)

= 9 (- ln ∣ cos (x) ∣)

Simplify

= - 9 ln ∣ cos (x) ∣

Add a constant to the solution

= - 9 ln ∣ cos (x) ∣ + C