Solve dydx=ytanx\frac{dy}{dx} = y \tan xdxdy=ytanx with y(0)=1y(0)=1y(0)=1.
y=secxy = \sec xy=secx
y=cosxy = \cos xy=cosx
y=esinxy = e^{\sin x}y=esinx
y=ln∣secx∣y = \ln|\sec x|y=ln∣secx∣