help with essential book questions!

[batchi94]

help would be great

1. The area of a circular disc increases from 100 cm2 to 101 cm2. Find the corresponding increase in the radius.
2. Given that y=x^-1/3, use calculus to determine an approximate value for 1/³√0.9.
3. The time for a swing, T seconds, of a pendulum of length l m is given by the rule T=2π√l/g, where g is constant.
i.) Find dT/dl.
ii.) Find the approximate increase in T when l is increased from 1.6 to 1.7. Give the answer in terms of g.
4. A 2% error is made in measuring the radius of a sphere. Find the percentage error in the surface area. (The surface area of a sphere is given by A = 4πr^2.)
5. One side of a rectangle is three times the other. If the perimeter increases by 2%, what is the percentage increase in the area?