Question 874212
cos(x)+sin(x)tan(x)=sec(x)



cos(x)+sin(x)*sin(x)/cos(x)=sec(x)



cos(x)+sin^2(x)/cos(x)=sec(x)



cos(x)*cos(x)/cos(x)+sin^2(x)/cos(x)=sec(x)



cos^2(x)/cos(x)+sin^2(x)/cos(x)=sec(x)



( cos^2(x) + sin^2(x) )/cos(x)=sec(x)



( 1 )/cos(x)=sec(x)



1/cos(x)=sec(x)



sec(x)=sec(x)



The identity is verified.