Arturo O. answered 05/07/20
Experienced Physics Teacher for Physics Tutoring
I assume the argument 0.02 is in radians.
f(x + Δx) ≅ f(x) + f'(x)Δx
f(x) = sin(x)
x = 0
Δx =0.02
f'(x) = cos(x)
sin(0 + 0.02) ≅ sin(0) + cos(0)(0.02) = 0 + 1(0.02) = 0.02
This result is consistent with the approximation
sin(x) ≅ x when x << 1 (x in radians).