SOLUTION: Find the exact value of {{{cos((1/2)cos^(-1)((-3)/4))}}}

Algebra ->  Trigonometry-basics -> SOLUTION: Find the exact value of {{{cos((1/2)cos^(-1)((-3)/4))}}}      Log On


   

Question 138823: Find the exact value of cos%28%281%2F2%29cos%5E%28-1%29%28%28-3%29%2F4%29%29
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
let




so




Substitute "2u" in for "u"


Multiply


Take the arccosine of the cosine of -3%2F4 to get -3%2F4


Replace with


Add 1 to both sides


Divide both sides by 2


Take the square root of both sides


Simplify


Rationalize the denominator if necessary



So