(1)△Ep=- X Fdx 0 GAx+Bx2) dx 0 Ax2_Bx 3 (2)△Ep=-°(-Ax+Bx2)dx 5.19 PB 2-3 目录结束=  ( Ax+B 2) 0 x x x d = A B 2 2 x 3 3 x = A B 2 3 5 19 ΔEP  F 0 = x x (1) d E ( A +B ) Δ P x 2 2 = 3 (2)  x dx 目录 结束