Angle between the planes x + y + 2z = 6 and 2x $$-$$ y + z = 9 is

If f(x) is an odd differentiable function defined on ($$-$$$$\infty $$, $$\infty $$) such that f'(3) = 2, then f'($$-$$3) is equal to

$$\int {{{\log \sqrt x } \over {3x}}} dx$$ is equal to

The equation x³ $$-$$ yx² + x $$-$$ y = 0 represents