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Find the number of terms in the expansion:

(1+2x+x^2)^20

**(1+2x+x ^{2})^{20} = (1+x)^{2}**

**so , ((1+x) ^{2})^{20} = (1+x)^{40}**

**so from binomial expansion ,we have **

^{40}c_{0} x^{40} +^{40}c_{1} x^{39} .............^{40}c_{40} x^{0}

**so total terms in the expansion will be 41. **

**(40 terms will be there from ^{40}c_{1} to ^{40}c_{40} + 1 term ^{40}c_{0}**

**so total terms will be 41)**