Question

integral of sec^4 x dx

Answer 1

so i have it split into sec^2 x and sec^2 x and converted one of the sec^2 x into tan x

Answer 2

split the sec^4 as sec^2 * sec^2

Answer 3

yes

Answer 4

i end up with tanx integral of sec^2 x why can i do a u sub for tan?

Answer 5

cant*

Answer 6

so, (1+tan^2) sec^2 dx
put t= tan x
dt =..?

Answer 7

ahhh. i see you used the identity. you end with integral of (1+u^2) du
du=sec^2 x

Answer 8

which is u+u^3/3

Answer 9

Damnit. Thanks

Answer 10

correct! welcome ^_^

Answer 11

don't forget to resubstitute back

Answer 12

yep. i always get stuck at whether to use an indentity or direct u sub.