integration急

given information:
f(x)=f(a-x)
∫ 1/(x^2+x+1)dx wherer upper limit=1,lower limit=0 = (sq.root of 3)x(pi/9)

∫ {(sinx)^2}/(1+sinxcosx)dx=∫ {(cosx)^2}/(1+sinxcosx)dx where upper limit=pi/2 and lower limit=0

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Question:
evaluate ∫ {(sinx)^2}/(1+sinxcosx)dx where upper limit=pi/2 and lower limit=0

when i try do this question, i met the difficulties:
i don't know how to integrate ∫ dx/(1+sinxcosx)

or is there any method to solve this question?