Question

Solution of the differential equation dy/dx = sin(x + y) + cos(x + y) is

(A) log|1 + tan((x + y)/2)| = y + c

(B) log|2 + sec((x + y)/2)| = x + c

(C) log |1 + tan(x + y)| = y + c 

(D) None of these

Answer 1

Answer is (D) None of these

Put x + y = v

Putting x + y = v. Then

Dividing numerator and denominator by cos (v/2) and integrating, we get