5. Find the general solution of sin x sin y dx + cos x cos y dy = 0 a) -sin y = C cos x b) sin y = C cos y c) sin x = C cos y d) None of the above 6. Find the general solution of xdx + V(a2-x2) dy = 0 a) y = v(a2-x2) + C b) x = v(a2-x2) + C c) y = v(a2+x2) + C d) None of the above