Let α denote an angle measured in degrees and define f(α)=αsinα.
(a) Evaluate α→0limf(α), clearly indicating how you convert between degree and radian measure in your calculation.
(b) Explain why the limit in part (a) differs from x→0limxsinx when x is measured in radians. Discuss the implications of this difference for the use of trigonometric limits in calculus and for the small-angle approximations common in physics and engineering.