# Trig help

• January 19th 2009, 06:44 PM
MOnroeMAth
Trig help
I have a bunch of questions that I thought I knew how to do and i cant get the right answers with my calculator. i have a ti-89.

The first question is " find the acute angel theta given cos(theta)=.3842"

the other question is how do i find "five other trigonometric function values given cos(theta)=.7"

Thank you very much
• January 19th 2009, 07:03 PM
Please do not double post ..
(1) $cos\theta=0.3842$

$cos^{-1}0.3842=....$

(2) Given that $cos\theta=0.7$ , the 5 other trigo function are sin , tan , cot, cosec,and sec .

Just draw a triangle ..
• January 20th 2009, 09:41 AM
FreeT
For question 1 work out: $cos^{-1}0.3842=\theta$

You mentioned your calculator wasn't working properly. Are you sure you have it on the degrees setting? Because if it's set on radians you'll get an answer of 1.17646, and if it's on grads you'll get 74.89546.

If you still can't get it to work properly, Windows have a program called calculator under accessories.