A parametric curve defined by x = cos π; y = sinπu22in

A parametric curve defined by x = cos π ; y = sin πu
2 2

in the range 0 ≤ u ≤ 1 is rotated about the X-axis by 360 degrees. Area of the surface generated is

x = cos	πu	; y = sin		-πu
	2			2

x² + y² =1
It represents a circle in x-y plane
0 ≤ 4 ≤ 1
∴ 0 ≤ 4 ≤ 1, 0 ≤ y ≤ 1
So, 0 ≤ θ < π/2
Area of hemisphere = 2π(r)²
= 2π(1)²
= 2π