∫0sin2xsin-1tdt+∫0cos2xcos-1tdt=
π4
π3
π2
π
Let t=sin2u in the first integral and t=cos2u in the second integral. Then
I1+I2=∫0xusin2udu-∫π/2xusin2udu
⇒I1+I2=∫0xusin2udu+∫xπ/2usin2udu=∫0π/2usin2udu
=-u2cos2u+14sin2u0π2
= π4