The curve is and the interval is
.
The surface area formula for rotation about the -axis is,
.
Differentiate the curve with respect to .
Apply formula: .
.
Substitute corresponding values in .
The surface area is .
Let , then
.
Evaluating boundaries :
\If , then
.
If , then
.
Substitute corresponding values in .
Apply formula: .
Hyperbolic sine function: .
The exact area of the surface by rotating the curve about the -axis is
square units.
The exact area of the surface by rotating the curve about the
-axis is
square units.