# A calculus problem by Jose Sacramento

Calculus Level pending

$\large \iint_R \cos \left( \dfrac{x-y}{x+y} \right) \, dx \; dy =\dfrac{\sin a}b$

Let $$R$$ be the region bounded by $$x+y=1,x=0,y=0$$. If the equation above holds true, find $$a+b$$.

×