Differentiate sin(x)cos(x) using the product rule.
The product rule states (assuming x' is the differential of x): (fg)′=f′g+fg′ Substitute the values into the rule: (sin(x)cos(x))' = sin(x)'cos(x) + sin(x)cos(x)' (sin(x)cos(x))' = cos2(x) - sin2(x)
