Find the curvature of y=sec x.

[Math10]

Homework Statement

Find the curvature of y=sec x.

Homework Equations

None.

The Attempt at a Solution

k(x)=abs(y")/[1+(y')^2]^(3/2)
y'=secx*tanx
y"=secx(sec^2 x+tan^2 x)
k(x)=abs(secx(sec^2 x+tan^2 x))/[1+(secx*tanx)^2]^(3/2)
how do I simplify this?

 

[mfb]

Are you sure it can be simplified? WolframAlpha finds suggestions, but I don't think they are simpler.