If the sum of the coefficients of and in the expansion of , is zero, then the value of is ______.
Answer: 21
Solution
The general term of is . The power occurs where and the power where , so , with coefficients and . Their sum is zero when , i.e. . Since , substitution gives , so .
JEE Main · 2026 · 05 Apr 2026 · Shift 1 · Integer answer