## Fundamental Identities

Trigonometric ratios and functions, the unit circle, inverse trig functions, identities, trig graphs, etc.

### Fundamental Identities

cos theata sec theata equals one

Posts: 1
Joined: Wed Mar 20, 2013 4:59 am

### Re: Fundamental Identities

Do you mean "cosine of theta times secant of theta equals one"?

$\cos(\theta)\, \sec(\theta)\, =\, 1$

What are you supposed to do with this?

Posts: 68
Joined: Sun Feb 22, 2009 11:12 pm

### Re: Fundamental Identities

I've been practicing these, and I think you're supposed to rewrite this in terms of cosine and sine only and verify that it equals 1.
$cos\theta sec\theta = 1$

converts to:
$cos\theta * (1/cos\theta) = 1$

Multiply through and you get:
$(cos\theta)/(cos\theta) = 1$

which does indeed equal 1 by basic division rules. Hope this helps and please tell me if I made a mistake!
agenta1013

Posts: 8
Joined: Thu Oct 17, 2013 2:20 pm