∫π23π2[2sinx]dx=
−π
0
−π2
π2
x=π2+t→I=∫2π[2cost]dt
=∫0π31dt+∫π3π20⋅dt+∫π22π3(−1)dt+∫2π3π(−2)dt
=π3−π6−2π3=−π2