Question 1155698


{{{cos(2t)/(cos(t)+sin(t))}}}...............use identity {{{cos(2t)=cos^2(t) - sin^2(t)}}}


={{{(cos^2(t) - sin^2(t))/(cos(t)+sin(t))}}}........factor numerator


={{{(cos(t) - sin(t)(cos(t)+sin(t)))/(cos(t)+sin(t))}}}....simplify


={{{(cos(t) - sin(t)cross((cos(t)+sin(t))))/cross((cos(t)+sin(t)))}}}


={{{cos(t) - sin(t)}}}