Hi, for this you need to use the product rule
y = uv, y' = uv' + u'v.
in this case u = e^2x and v = cosx
so u' = 2e^2x and v' = -sinx
combined this give y' = 2(e^2x)cosx - (e^2x)sinx
Hope that helps.
I am revising on "Differentiating Trig functions" and I am stuck on a question I am not so sure about. I understand the rules such as the quotient rule, product rule etc. But for this it's not working out.
Differentiate y = e^2x cos x