### Home > CALC > Chapter 4 > Lesson 4.2.1 > Problem4-48

4-48.

Let h(x) = (x² + 1)(x − 4) and note its derivative (you found the derivative in problem 4-47).

If h(x) = f(x)g(x), then f(x) = x² + 1 and g(x) = x − 4. Find the f '(x) and g'(x).

Multiply: f '(x)g'(x) = . Is this the same derivative you found in problem 4-47?

During this course, you will discover many shortcuts to finding derivatives, but this is not one of them. h'(x) ≠ f '(x)g'(x)