Please anyone solve ASAP!
Bruh even I didn’t get this question while attempting this paper…
You’ve gotta observe that it’s the multiplication of (1+x)^20*(1+x)^20 series. So that will yield (1+x)^40. Which in turn gives us the summation 40Cr. We know that nCr maximum value lies at nCn/2.
Thus r=20. This was what PNM sir (Resonance) did. I’ve not found any other approach.
How is it the multiplication of (1+x)^20 * (1+x)^20???
Arey multiplying first with last term of each expression.
watch from 36:23
Haa. I got it…
When you the same terms as given in question and add you see that they are the coefficients of X^R and so now to compare you need find coefficient of X^R in (1+x)^40 which is 40CR…
And hence its maximum is r=20…!