f（z）=z方-2z-3,z+1的模长大于4，小于正无穷，展开为洛朗级数

Question

如题所述

Answer 1

方程整理：x1=y²/4 x2=1
建立微分：在y=y处,dVy=π（x2²-x1²)dy=π[1²-(y²/4)^2]dy
∴Vy=∫【-2,2】{π[1-y^4/16]}dy
=2∫【0,2】[π(1-y^4/16)]dy
=2π(y-y^5/80)【0,2】
=(2*2-2*32/80)π
=16π/5