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

The correct option is D $13$

No. of terms in the first expression is $25+1=26$.
No. of terms in the second expression is $25+1=26$.
Due to minus sign, half of the terms get cancelled.
$\therefore$ no. of terms after simplification $=13$