- #1
takando12
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Homework Statement
If 1/2<=x<=1
, then cos-1[ x/2 + (√(3-3x2))/2] + cos-1 x is equal to?
Homework Equations
The Attempt at a Solution
Substituting x=cosθ
= cos-1(cosθ) + cos-1 [ cos(θ)/2 + (√(3(1-cos2(θ)))/2]
= θ + cos-1 [cos (π/3) cos θ + sin (π/3) sinθ]
= θ + cos-1 [cos (θ -(π/3)]
= 2θ -(π/3)
= 2 cos-1x -(π/3)
But the correct answer according to the book is π/3. Please help me understand what I've done wrong.
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