삼각함수 미분*

\[ y=\sin x \to y’=\cos x\] \[ y=cos x \to y’=-\sin x \]

\[ y=\sin ax \]\[\to y’=(ax)’\cos ax=a\cos ax\] \[ y=cos ax \]\[ \to y’=-(ax)’\sin ax=-a\sin ax \]

\[ \int\sin xdx =-\cos x\] \[ \int\cos x dx=\sin x \]\[\int\cos axdx =\frac{1}{(ax)’}\cdot\sin ax=\frac{1}{a}\sin ax\]

\[ \sin(x ±y)=\sin x \cos y±\cos x\sin y\]\[\cos(x±y)=\cos x \cos y \mp \sin x \sin y\]