Introduction: Many composite functions can be differentiated without splitting the function into two parts. If this is not possible, you must use the chain rule.
Rule: Let $y(x) = u(v(x))$ be a Composite function. Then:
$$ y'(x) = u'(v(x)) \cdot v'(x).$$
Rule: Let $y(x) = u(v(x))$ be a Composite function. Then:
$$ y'(x) = u'(v(x)) \cdot v'(x).$$