# Help Integrating Trig functions

• August 4th 2008, 02:19 AM
Gigabyte
Help Integrating Trig functions
How would one go about integrating
sec(x)dx
using a substitution??
Please go through all the steps required
Thanks
• August 4th 2008, 02:26 AM
mr fantastic
Quote:

Originally Posted by Gigabyte
How would one go about integrating
sec(x)dx
using a substitution??
Please go through all the steps required
Thanks

There's the simple but unobvious approach. Read this: Integral sec(x)

Then there's the more routine but tedious approach that involves the Weiestrass substitution. Read this: PlanetMath: Weierstrass substitution formulas
• February 28th 2009, 10:00 AM
Krizalid
Quote:

Originally Posted by transgalactic

i ll get a very complicated expression
is there an easier way??

Not actually an easier way but at least works.

$\frac{1}{\cos x}=\frac{\cos x}{\cos ^{2}x}=\frac{\cos x}{1-\sin ^{2}x},$ following up on this put $u=\sin x$ and solve the remaining integral.