2011*2012*2013*2014*2015+1
find square root of the above number.

Hi Keshav,

Here's a solution, slightly tricky:

Let 2011 = x

So x(x+1)(x+2)(x+3) + 1 = (x²+3x)(x²+3x+2) + 1 = (x²+3x)² + 2(x²+3x) + 1 = (x²+3x+1)²

So square root of that would be x²+3x+1

Where x = 2011.

Which is 2011²+3*2011+1 = 2011*2014+1 = 4050155.

Hope that helps.

All the best.

Regards,

Ashwin (IIT Madras).