For questions 8, 9, 10: Note that x² + y2 12 is the equation of a circle of radius 1. Solving for y we have y=√1-22, when y is positive.
8. Compute the length of the curve y = √1-x^2 between x = 0 and x = 1 (part of a circle.)
9. Compute the surface of revolution of y= √1-x^2 around the z-axis between x = 0 and x = 1 (part of a sphere.)