The point on the curve y=cos(x+y), 0≤x≤π, at which the tangent is parallel to x+2y=0 is

Given curve y=cos(x+y) dydx=−sin(x+y)1+sin(x+y) Slope of the line x+2y=0 Slope of the line is=−12 Slope of the tangent M=(dydx)p=−sin(x+y)1+sin(x+y)     By verification slope of tangent at (π2,0)=−12