$$(\sum_{n=1}^{9}{n})^2$$
You asked:
Evaluate the expression: \({\sum_{n = 1}^{9} {n}}^{2}\)
MathBot Answer:
\[\left(\sum_{n=1}^{9} n\right)^{2} = 2025\]
$$\begin{aligned}\left(\sum_{n=1}^{9} n\right)^{2} &= \left(\frac{9 \cdot \left(1 + 9\right)}{2}\right)^{2} \ \ \ \small{\color{grey}\text{by the identity} \sum_{n=1}^{m} n = \frac{m(m+1)}{2}}\\&= 45^{2}\\&= 2025\end{aligned}$$