precalc
posted by Kim on .
find the exact value of the given expression. Thank you!
tan(1/2cos^1(9/10)

tangent of 1/2 the angle whose cosine is 9/10
Exact value? What is wrong with a calculator? Paste this into your google search window...
tan(.5*arccos(9/10))=
Is that exact enough? It appears to be an irrational number. 
find the exact value of (5pie/8)