## anonymous one year ago I'm confused a little... How does the integral of secxtanx = secx ?

1. anonymous

it doesnt ._.

2. anonymous

Really? XD lol Then what is is?

3. anonymous

it*

4. anonymous

sec(theta)=$\frac{ 1 }{ \cos*theta}$

5. anonymous

Right

6. jim_thompson5910

if y = sec(x), then dy/dx = sec(x)*tan(x) take this in reverse to get $\Large \int(\sec(x)\tan(x))dx = \sec(x) + C$

7. anonymous

Ohhh right! That makes sense!!

8. jim_thompson5910

if you had no idea that dy/dx = sec(x)*tan(x) then you can convert sec(x)*tan(x) into (1/cos)*(sin/cos) which becomes sin/(cos^2) from there you use u-sub u = cos(x) du = -sin(x)dx

9. UsukiDoll

that's one of the standard derivative definitions... The derivative of secx is secxtanx the antiderivative of secxtanx is secx.

10. anonymous

Yeah I would've had to go through it with u-sub... i didn't know that dy/dx of secx = secxtanx

11. anonymous

Right! Thanks you guys! That really helped!

12. jim_thompson5910

you're welcome

13. anonymous

:)