Find the value dy/dx if y=1+ sinx - cosx ÷1+ sinx + cosx

firstly,try to make y in a simpler form by using formulas as [1-cosx = 2(sin²x/2) ],[ 1+cosx =2(cos²x/2) ] and sinx = 2 sin(x/2) .cos(x/2).after putting these in your question and taking 2sin(x/2) common from numerator and 2 cos(x/2) from denominator your Y will reduced to tan (x/2) and thus its derivative is given by sec²(x/2) / 2.