- #1

- 144

- 0

## Homework Statement

[itex]sec^{2}(x)tan(x)dx[/itex]

I can let u = tanx

then du = [itex]sec^{2}(x)[/itex]

[itex]\frac{1}{2}\int udu[/itex]

[itex]\frac{1}{2}tan^{2}(x)[/itex]

OR

I can let u = secx

then du = secxtanx dx

[itex]\int udu[/itex]

[itex]\frac{1}{2}u^{2}[/itex]

[itex]\frac{1}{2}sec^{2}(x)[/itex]

Why do both work? Which one is correct? Or are both correct?