3 ms·I could forget something but sin'(ax) = cos(ax). If a is a constant factor.by bvrmn 4y agoI could forget something but sin'(ax) = cos(ax). If a is a constant factor.cygx 4y agoYou need to apply the chain rules, ie sin'(ax) = a cos(ax)bvrmn 4y agoThank you. I'm really bad at calculus.