Q175 / 270 · NDA 2013 (Phase 2) · Mathematics
How many terms are there in the expansion of $\left(1+2 x+x^2\right)^{10} ?$
- A11
- B20
- Correct answerC21
- D30
Solution
$\left(1+2 x+x^2\right)^{10}=\left\{(1+x)^2\right\}^{10}=(1+x)^{20}$
We know that number of terms in the expansion of $(1+x)^n$ are $n+1$
so, required number of terms $=20+1=21$.
Hence, the correct answer is option: 'C'.