- Thread starter
- #1

#### karush

##### Well-known member

- Jan 31, 2012

- 3,181

$$\int{t}^{3}\sqrt{1+{t}^{2}} \ dr

=\frac{\left({t}^{2}+1\right)^{5/2}}{5}

-\frac{\left({t}^{2}+1\right)^{3/2}}{3}+C$$

$$t=\tan\left({u}\right) \ \ \ dt=\sec^2\left({u}\right) \ du $$

Substituting

$$\int\tan^3\left({u}\right)\sec^3\left({u}\right) \ du $$

Which doesn't look like a good option ??