I'm pretty sure you can solve the integral of sec^3 by doing integration by parts
Take sec^2 and sec as your two parts and try that
I need to integrate the following:
7*sqrt(x^2+9)
Here is my work so far:
x=3tan(theta)
d-x=3sec^2(theta)*d-theta
Then:
7*int[sqrt{9tan^2(theta)+9}*3sec^2(theta)*d-theta
Then:
63*int[sec^3(theta)*d-theta]
And I don't know what to do from there. Thank you!