List the first 3 terms, then evaluate

.

Step-by-step explanation:

The given expression is

We need to find first 3 terms, then we have evaluate the value.

Here,  

For i=1,

For i=2,

For i=3,

So first three terms are -1,-3,-5. It is an AP with first term -1 and common difference -2. So, next 7 terms are -7,-9,-11,-13,-15,-17,-19.

Now,  

Therefore, the value of is -100.