Derivative Trig Functions - Math.com - World of Math Online
Proofs of Derivative of Trig Functions Proof of sin(x): algebraic Method Given: lim(d->0) sin(d)/d = 1. Solve: sin(x) = lim (d->0) ( sin(x+d) - sin(x) ) / d = lim ( sin(x)cos(d) + cos(x)sin(d) - sin(x) ) / d = lim ( sin(x)cos(d) - sin(x) )/d + lim cos(x)s...