由2x+y+8=0得:
y=-2x-8,代入y=x²-8,得:x²+2x=0
x(x+2)=0
x=0或x=-2
∫[-2:0][(-2x-8)-(x²-8)]dx
=∫[-2:0](-x²-2x)dx
=(-⅓x³-x²)|[-2:0]
=(-⅓·0³-0²)-[-⅓·(-2)³-(-2)²]
=4/3
所求围成的面积为4/3
y=x^2=3x+4x^2-3x-4=0(x-4)(x+1)=0x=-1,x=4二者交于A(-1,1),B(4,16)所围成的图形面积S=∫(3x+4-x^2)dx(-1->4)=(-x^3/3+3x^2/2+4x)(-1->4)=(-64/3+24+16)-(1/3+3/2-4)=125/6