Prove that if fix) is a derivation for every x then so is the function U(x] =x3 -f(3x2) Shear per every 1:. Suppose now that tangent of U(x) in point (-1, 0.5) is 2y - 101' = l I What is the slope of x) in point x: - 5? We will define 30:} = f(5i|11') , HI) = 'l+'|"l_05]' Solve