Question

Find the exact value of the expression.

Sin^2(1/2 cos^-1 (4/5))

Answer 1

well what do you have to do first?

Answer 2

I got a 0.1

Answer 3

do i have to use?: cos 2ß = 1 - 2 sin² ß where ß =[ arccos 4/5 ] / 2

Answer 4

well, you have a half angle inside, not a double

Answer 5

But, you should know the exact value of arccos(4/5) It's a special triangle

Answer 6

But anywho, check out this webpage and I believe you will find something you like very much http://www.sosmath.com/trig/douangl/douangl.html