求y=x눀与x=y눀所围成的图形的面积,并求此图形绕x轴旋转一周所生成的旋转体的体积。要详细步骤

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2025-05-11 10:04:59
推荐回答(2个)
回答1:

解:
y=x²与x=y² 的交点为:x1=0;y1=0;
x2=1;y2=1;

相交区域位于第一象限,x=y² ==> y =√x ,面积:
S = [0,1]∫(√x - x²)dx = (2/3*x√x - x³/3)|[0,1] = 1/3
若图形围绕x轴旋转,则在横坐标=x 处,以dx为厚度形成的圆环形体及维元为:
dV = π[(√x)² -(x²)²]*dx = π(x - x^4)*dx
V = [0,1]∫ π(x - x^4)*dx = π(x²/2 - x^5/5) |[0,1] = 0.3π

回答2:

y=x²与x=y² 的交点为:x1=0;y1=0;
x2=1;y2=1;

相交区域位于第一象限,x=y² ==> y =√x ,面积:
S = [0,1]∫(√x - x²)dx = (2/3*x√x - x³/3)|[0,1] = 1/3
若图形围绕x轴旋转,则在横坐标=x 处,以dx为厚度形成的圆环形体及维元为:
dV = π[(√x)² -(x²)²]*dx = π(x - x^4)*dx
V = [0,1]∫ π(x - x^4)*dx = π(x²/2 - x^5/5) |[0,1] = 0.3π