Tuesday
May 21, 2013

# Homework Help: algebra

Posted by Carmen on Monday, June 2, 2008 at 9:18pm.

Evaluate giving exact values and identities. Calculator based solutions are not acceptable. Thanks for any help
cos (-5pi/12)

• algebra - drwls, Tuesday, June 3, 2008 at 2:08am

That is -75 degrees. Use the formula for cos (A + B), where A = -45 degrees and B = -30 degrees.

cos (-5pi/12) = cos (5pi/12)
= cos45deg*cos30deg - sin45deg*sin30deg
= (sqrt2)/2*(sqrt3)/2 - sqrt2/4
= [(sqrt6)- (sqrt2)]/4
= sqrt2*(sqrt3 -1)/4

 First Name: School Subject: Answer:

Related Questions

trig - Evaluate giving exact values and identities. Calculator based solutions ...
algebra - Evaluate giving exact values and identities. Calculator based ...
trig - Evaluate giving exact values and identities. Calculator based solutions ...
algebra - Evaluate giving exact values and identities. Calculator based ...
algebra - Evaluate giving exact values and identities. Calculator based ...
statistics - Evaluate giving exact values and identities. Calculator based ...
trig - Evaluate giving exact values and identities. Calculator based solutions ...
trig - Evaluate giving exact values and identities. Calculator based solutions ...
trig - 2sin(x)cos(x)+cos(x)=0 I'm looking for exact value solutions in [0, 3...
math - use exact values of the sin,cos and tan of (pi/3) and (pi/6)(which I have...

For Further Reading

Search
Members
Community
FEATURES