The coefficient of x^n, n N , in the expansion of 1+x 1+x^2 is

JEE Advanced Mathematics question

The coefficient of , , in the expansion of is

Answer: (A),(D)

For ,

=(1+x)\{1-+-+(- +\}.

The second factor has only even powers, with having coefficient . - (even): only the "1" from contributes, giving . So (a) ✔. Option

Create a free account to read the complete working (4 steps), and practise questions like this in a timed test.

Question ID VK-108437