# Trig Proof

• March 10th 2010, 08:32 PM
Brndo4u
Trig Proof
Im caught up on this proof... need some help

CosX/SecX+SinX/CscX=Sec^2X-Tan^2X
• March 10th 2010, 09:29 PM
Jhevon
Quote:

Originally Posted by Brndo4u
Im caught up on this proof... need some help

CosX/SecX+SinX/CscX=Sec^2X-Tan^2X

Note that the left hand side is $\cos^2 x + \sin^2 x = 1$

Now recall that $1 + \tan^2 x = \sec^2 x$

What can you conclude?
• March 11th 2010, 12:40 AM
db5vry
Quote:

Originally Posted by Brndo4u
Im caught up on this proof... need some help

CosX/SecX+SinX/CscX=Sec^2X-Tan^2X

Think of $secx$ as $\frac{1}{cosx}$ and $cosecx$ as $\frac{1}{sinx}$. when you've got something like

$\frac{cosx}{1/cosx}$ then do you think that this could equate to $cos^2 x$? Does this help you for the rest of the question if you can recall other identities that you need?
• March 11th 2010, 06:33 AM
Brndo4u
Yes, that I see what you guys are saying... I need to use the Recip ID, Which in the end will give me Sin^2 & Cos^2. That will become 1 and Sec^2 & Tan^2 will also be 1...So, 1 =1