Homework Help: Trigonometry

Posted by Lucy X on Sunday, December 7, 2008 at 8:21pm.

Hi, I need help with this question:

Use the addition and subtraction formulas ti fubd the exact values of the trigonometric ratios:

cos(-7pi/12)

Okay, I'm just having trouble with a rather basic part of the question...

I wrote cos(pi/4 + pi/3), but now I realized that the trig ratio is negative. How do I write -7pi/12 as the sum/difference of two trig ratios?

No one has answered this question yet.

Answer this Question

Related Questions

Math- Trig - 1. Determine the exact value of cos^-1 (pi/2). Give number and ...
MATH - 1.)Find the exact solution algebriacally, if possible: (PLEASE SHOW ALL ...
trig - given that 1/2pi<theta<pi and sin theta=1/5, use ...
trig - Evaluate giving exact values and identities. Calculator based solutions ...
algebra - Evaluate giving exact values and identities. Calculator based ...
CALCULUS - If cos(t)=–7/9, find the values of the following trigonometric ...
trig - 2sin(x)cos(x)+cos(x)=0 I'm looking for exact value solutions in [0, 3...
math - Eliminate the parameter (What does that mean?) and write a rectangular ...
Trigonometry - I'm confused about how to get the answer of this question. If...
Math - Use an addition or subtraction formula to write the expression as a ...

For Further Reading

First Name:
School Subject:
Answer: