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
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