NDA2019MathematicsBinomial TheoremActual
How many terms are there in the expansion of (1+2 x+x^2 )^5+ (1+4 y+4 y^2 )^5 ?
Options
- A12
- B20
- C21
- D22
Correct answer
C. 21
Step-by-step solution
aligned & (1+2 x+x^2 )^5+ (1+4 y+4 y^2 )^5 & = [(1+x)^2 ]^5+ [(1+2 y)^2 ]^5 & =(1+x)¹⁰+(1+x y)¹⁰ & Total numbers of terms in each of them is 11 but constant & term will be added & Total terms =11+11-1 & =21 aligned