How do I get the derivative of a summation Sorry if this has been asked before. I'm fairly new to this.
How do I find the derivative of a summation?

$$f(x)= \sum_{i=1}^{10} \frac{10x^2}i$$

what is the derivative of $f(x)$?
Note that $$f(x)=\sum_{i=1}^{10}\frac{10x^2}{i}$$
$$f(x)=10x^2\cdot \sum_{i=1}^{10}\frac{1}{i}$$
$$\implies f'(x)=20x\cdot \sum_{i=1}^{10}\frac{1}{i}$$
Simple derivative on $x$.
$f(x) = 10x^2/1+10x^2/2+\cdots + 10x^2/10$ Now termwise differentiate.