In the expansion of $(1+x)^n$ $\frac{C_1}{C_0}+2 \frac{C_2}{C_1}+3 \frac{C_3}{2}+\ldots+n \frac{C_n}{C_{n-1}}$ is equal to

If $$n$$ is even and the middle term in the expansion of $$\left(x^2+\frac{1}{x}\right)^n$$ is $$924 x^6$$, then $$n$$ is equal to

The number of terms in the expansion of $$(x+y+z)^{10}$$ is

The number of terms in the expansion of $$\left(x^2+y^2\right)^{25}-\left(x^2-y^2\right)^{25}$$ after simplification is