Find the Mistake in Homework Statement

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Homework Statement



π^2
4
∫ COS(√x) dx
0

Homework Equations





The Attempt at a Solution



t=√x ; x=t^2 ; dx= 2t

π
2
∫ COSt · 2t dt = [SINt · 2t ] - ∫ 2SINt dt = π +2
0

yes but.. where is the mistake?
'cause the result is: π/2 - 1

thanx a lot
 
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The answer should be [itex]\pi - 2[/itex]. Check the substitutions in the final step.
 
Neutrino is right, the result is π - 2, but why does the book report a π/2 - 1 result?