# I think that my integral is wrong

1. Jul 29, 2007

### Robert Mak

Integral of ((Tan x)^6)dx

i think that the solution is:

(1/5)(tan x)^5 + (1/3)(tan x)^3 - (2/3)(tan x)^3 + tan x - x + c

but if i derivate this solution it lead me to that:

(tan x)^4((tan x)^2 + 2)

?????????????????????????

2. Jul 29, 2007

### ^_^physicist

Yes, your integral is incorrect; however, try expanding the expression and then integrating.

3. Jul 29, 2007

### Dick

I think your integral is correct. It must be the differentiation that is causing the problem. But no one can tell you why until you show your work.

4. Jul 30, 2007

### cristo

Staff Emeritus
It looks correct to me, also (although, why you haven't collected those terms in tan^3x, I don't know!)

5. Jul 30, 2007

### Gib Z

I think he might forgetting to use the Chain Rule.

6. Jul 30, 2007

### Robert Mak

Thanks people; i did a mistake of signs lol.