write the summation notation of this sequence: 1-1/4+1/9-1/16+1/25-1/36+...

Question

I need this in sigma notation

Answer 1

Notice that the series is alternating and each denominator is a square number, so we can represent this:

∑^∞_n=1 (-1)^n-1/n²

When n is odd, the nth term will be positive, and when even, it'll be negative.

Hope this helped!