SOLUTION: find cos x/2, given: sin x = 1/4, 360 < x < 450, use half-angle identity to find the exact value.
Algebra.Com
Question 453317: find cos x/2, given: sin x = 1/4, 360 < x < 450, use half-angle identity to find the exact value.
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
find cos x/2, given: sin x = 1/4, 360 < x < 450
------
cos(x/2) = +/- sqrt[(1+cos(x))/2]
----
Since sin(x) = 1/4, y = 1 and r = 4
---
So x = sqrt[4^2-1^2] = sqrt(15)
----
Therefore cos(x) = x/r = sqrt(15)/4
=====
So, cos(x/2) = +/- sqrt[(1+[sqrt(15)/4]]/2]
=======================================================
Cheers,
Stan H.
===============
RELATED QUESTIONS
Use a double- or half-angle identity to find the exact value of each trigonometric... (answered by lwsshak3)
Use a half-angle identity to find the exact value of this expression.
Given... (answered by Edwin McCravy)
Suppose x= 7pi/12. Use half-angle identity to find the exact value of... (answered by lwsshak3)
Use the half-angle identity to find the exact value of... (answered by stanbon)
Use a half angle identity to find the exact value of... (answered by stanbon)
Use a half-angle identity to find the exact value of the expression. sin 112.5... (answered by robertb)
use a half angle identity to find the exact value of the expression
sin 105... (answered by lwsshak3)
Use half-angle identity to find the exact value of... (answered by solver91311)
θ=157.5° Use a half-angle identity to find the exact value of... (answered by stanbon)