Find the derivative of
Let f(x) =
By product rule,
= (5x3 + 3x – 1) + (x – 1)(15x2 + 3)
= 5x3 + 3x – 1 + 15x3 + 3x – 15x2 – 3
= 20x3 – 15x2 + 6x – 4