I'm stuck with the following problem:
Estimate the relative uncertainty of the surface of a sphere if the measure of its radius is accurate to $2.0 \%$.
My work so far:
Sphere surface: $ 4\pi r^2 $
Formula for relative uncertainty: $ \left(\dfrac{|df|}{f} \times 100 \right) \% $ is equal to $ \left(\dfrac{\left \lvert f'(x)dx \right \rvert}{f(x)} \times 100 \right) \% $
My function : $ F(x) = 4\pi r^2 $
Thanks.