# Trig problem

• Apr 18th 2009, 07:50 PM
scottsw1
Trig problem
I have to express the given trigonometric function in terms of the indicated function.

cos theata in terms of sec theata.

• Apr 18th 2009, 07:58 PM
Jhevon
Quote:

Originally Posted by scottsw1
I have to express the given trigonometric function in terms of the indicated function.

cos theata in terms of sec theata.

by definition: $\displaystyle \sec \theta = \frac 1{\cos \theta}$

just solve that for $\displaystyle \cos \theta$ (make it the subject of the formula)
• Apr 18th 2009, 08:02 PM
lekhabhatt81
All i know is sec is the inverse of cos. see, if it works for you and help you solve your problem.
• Apr 18th 2009, 08:07 PM
Jhevon
Quote:

Originally Posted by lekhabhatt81
All i know is sec is the inverse of cos. see, if it works for you and help you solve your problem.

it is better to say "reciprocal" than "inverse" here. the inverse of $\displaystyle \cos x$ is $\displaystyle \cos^{-1} x$ (or $\displaystyle \arccos x$), and this is different from $\displaystyle \sec x$
• Apr 18th 2009, 08:16 PM
lekhabhatt81
You are indeed correct. Sec is the reciprocal of cos. thanks buddy! :)
• Apr 19th 2009, 06:51 AM
scottsw1
I am lost, please help. I know that sec=1 over cos, but what forumlua do I use to work the problem?
• Apr 19th 2009, 04:56 PM
lekhabhatt81
could you put in the entire question? because with what you have put up... this is all that can be said, i guess.
• Apr 19th 2009, 07:59 PM
scottsw1
Express the given trigometric function in terms of the indicated fucntion:
cos theta in terms of sec theata.
• Apr 19th 2009, 08:10 PM
Jhevon
Quote:

Originally Posted by scottsw1
Express the given trigometric function in terms of the indicated fucntion:
cos theta in terms of sec theata.

you already have the formula. i told you the formula. just solve for cosine
• Apr 20th 2009, 07:23 PM
scottsw1
Please show me how to work the entire problem out. Thanks.
• Apr 20th 2009, 07:28 PM
pickslides
Quote:

Originally Posted by scottsw1
Please show me how to work the entire problem out. Thanks.

Jhevon has solved the problem for you as best it can be solved with the information you have given. Are there any further values you have not supplied?
• Apr 20th 2009, 08:48 PM
scottsw1
Here is a photocopy of the problem:
http://farm4.static.flickr.com/3619/...c5c8a712db.jpg
• Apr 21st 2009, 03:39 PM
scottsw1
Does the link show an insight on how to solve the problem?
• Apr 21st 2009, 03:51 PM
pickslides
I looked at the link.

Some of the problems are written very strangly. For example in ther first problem the first sec part of the equation seems to be raised to the power of something. But what?