#(df)/dx = d/dx e^x/sinx - d/dx cosx/e^x#
#(df)/dx = (e^xsinx-e^xcosx)/sin^2x - (-e^xsinx - e^xcosx)/e^(2x)#
#(df)/dx = e^x ((sinx-cosx)/sin^2x + (sinx - cosx)/e^(2x))#
#(df)/dx = e^x (e^(2x)(sinx-cosx)+ sin^2x(sinx - cosx))/(e^(2x)sin^2x )#
#(df)/dx = ((e^(2x)+sin^2x)(sinx-cosx))/(e^xsin^2x )#