Question

The number of terms in the expansion of $(x^2+y^2{)}^{25}-(x^2-y^2{)}^{25}$ after simplification is

• A. 26
• B. 0
• C. 50
• D. 13

Answer 1

Answer: (D)

${\left(a+b\right)}^n-{\left(a-b\right)}^n$ if n is odd
On simplification we get $\frac{n+1}{2}$ terms $i.e.,\frac{25+1}{2}=13$ terms