## Calculus 8th Edition

Differentiate $y=\frac{\sin t}{1 +\tan t}$ $y'=\frac{\cos t + \sin t -\tan t\sec t}{(1+\tan t)^2}$
Differentiate using quotient rule and trig rules. $y' =\frac{\cos t(1+\tan t) - \sin t(\sec ^2t)}{(1+\tan t)^2}$ $=\frac{\cos t + \sin t -\tan t\sec t}{(1+\tan t)^2}$