Let's differentiate: ddx(sin(x2 + 3x + 1)) Apply the differentiation rule: ddx(sin(f)) = ddx(f)·cos(f) with f = x2 + 3x + 1 ddx(x2 + 3x + 1)·cos(x2 + 3x + 1) (ddx(x2) + ddx(3x) + 0)·cos(x2 + 3x + 1) ℹddx(x2) = 2x‖ddx(3x) = 3 (2x + 3)·cos(x2 + 3x + 1) ▶Derivative: cos(x2 + 3x + 1)·(2x + 3)