Question:
Find the ratio of the coefficients of $x^{\rho}$ and $x^{q}$ in the expansion of $(1+x)^{p+q}$.
Solution:
Coefficient of $x^{p}$ in the expansion of $(1+x)^{p+q}$ is $^{p+q} C_{p}$.
Coefficient of $x^{q}$ in the expansion of $(1+x)^{p+q}$ is $^{p+q} C_{q}$.
Now,
$\frac{p+q_{p}}{p+q_{q}}=\frac{\frac{(p+q) !}{p l q !}}{\frac{(p+q) !}{q ! p !}}=1$
Hence, the ratio of the coefficients of $x^{p}$ and $x^{q}$ in the expansion of $(1+x)^{p+q}$ is $1: 1$.