Binomial Theore...

In the expansion of $$\left( 1+ \right) ^{ 50 },$$ the sum of the coefficient of odd powers of x is _______.

Find the middle term(s) in the expansion of :
$$\left(2ax-\dfrac{b}{x^{2}}\right)^{12}$$

The constant term in the expansion of $$(x^{2}-\frac{1}{x^{2}})^{16}$$ is 

Find the middle term(s) in the expansion of :
$$\left(2x-\dfrac{x^{2}}{4}\right)^{9}$$

The coefficient of the middle term in the binomial expansion in powers of x of $$(1+\alpha x)^{4}$$ and of $$(1-\alpha x)^{6}$$ is the same if $$\alpha $$ equals : 

Find the middle term in the expansion of 
$$\left(\dfrac{2}{3}x-\dfrac{3}{2x}\right)^{20}$$

Find the middle term in the expansion of :
$$\left(x^{2}-\dfrac{2}{x}\right)^{10}$$

Find the middle term(s) in the expansion of :
$$\left(3x-\dfrac{x^{3}}{6}\right)^{9}$$

Find the middle term(s) in the expansion of :
$$\left(\dfrac{p}{x}+\dfrac{x}{p}\right)^{9}$$

Find the coefficient of $$x^{7}$$ in the expansion of $$\left(x-\dfrac{1}{x^{2}}\right)^{40}$$