Find the coefficient of `x^5` in the expansion of `(1+x)^(21)+(1+x)^(22)++(1+x)^(30)dot`

Explanation

To find the coefficient of \( x^5 \) in the expansion of \( (1+x)^{21} + (1+x)^{22} + \ldots + (1+x)^{30} \), we can follow these steps:

### Step 1: Write the expression
We start with the expression:
\[ (1+x)^{21} + (1+x)^{22} + (1+x)^{23} + (1+x)^{24} + (1+x)^{25} + (1+x)^{26} + (1+x)^{27} + (1+x)^{28} + (1+x)^{29} + (1+x)^{30} \]

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