Question

summation question. i have to write iout the summarion and find the answer

Answer 1

We need to solve the next summation:

$\sum_{i\mathop{=}2}^5(-1-2i)$

i represents the value where we start and 5 represents the value where we need to go.

So, we need to sum by changing the i variable starting with 2 until 5.

Then:

$\begin{gathered} \sum_{i\mathop{=}2}^5(-1-2i)=(-1-2(2))+(-1-2(3))+(-1-2(4))+(-1-2(5)) \\ =-5+(-7)+(-9)+(-11) \\ =-5-7-9-11 \\ =-32 \end{gathered}$

Hence, the answer is -32.