# what's the integral of (tanx)^2

#### jessicak

##### Senior member
i don't need to know how to integrate it and my book doesn't have this one on a formula sheet and I was just wondering if anyone knew of the top of their heads what the answer is. Thanks

#### GiLtY

##### Golden Member
Hint: Think about a trig identity that involves Tangent^2 and Secant^2

--GiLtY

#### MustangSVT

##### Lifer
dual tank?

edit-- oops.. it was Tangent X not tank^2.

#### Vortex22

##### Diamond Member
I don't know what I'm talking about... but I found this.
It says the answer is (tan^2)(x^3)/3

#### RaynorWolfcastle

##### Diamond Member
Listen to GiLty, that's the right method and solving it is easy.

#### PowerMacG5

##### Diamond Member
int(tan(x)^2)dx = int(sec(x)^2-1)dx

Then its simple from there.

#### DrPizza

##### Administrator Elite Member Goat Whisperer
Originally posted by: Vortex22
I don't know what I'm talking about... but I found this.
It says the answer is (tan^2)(x^3)/3

Should have clicked on the link that shows how to input the integral... you typed it in wrong.

#### MichaelD

##### Lifer
Originally posted by: Marauder911
int(tan(x)^2)dx = int(sec(x)^2-1)dx

Then its simple from there.

Oh yeah...absolutely.....PFFFT!!!

After getting thru so many years on this earth, I still can't believe that there are humans that can actually make sense of sh2t like this...I mean, WTF do you USE this FOR?

#### RaynorWolfcastle

##### Diamond Member
Originally posted by: MichaelD
Originally posted by: Marauder911
int(tan(x)^2)dx = int(sec(x)^2-1)dx

Then its simple from there.

Oh yeah...absolutely.....PFFFT!!!

After getting thru so many years on this earth, I still can't believe that there are humans that can actually make sense of sh2t like this...I mean, WTF do you USE this FOR?

building your computer, car, and many other things... I'm serious, too.

#### MichaelD

##### Lifer
Originally posted by: RaynorWolfcastle
Originally posted by: MichaelD
Originally posted by: Marauder911
int(tan(x)^2)dx = int(sec(x)^2-1)dx

Then its simple from there.

Oh yeah...absolutely.....PFFFT!!!

After getting thru so many years on this earth, I still can't believe that there are humans that can actually make sense of sh2t like this...I mean, WTF do you USE this FOR?

building your computer, car, and many other things... I'm serious, too.

I can build a PC, frame a house, tape and float sheetrock, paint, do basic household wiring, rebuild an engine, field strip an M16 in the dark, solder a small PCB, clean a bathroom, do needlepoint, cook Italian food that would make Emiril go "BAM!" but yet I have no use for this equation. If I can't use it, it's friggin' useless.