- #1

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## Homework Statement

Evaluate:

[tex]^{30}C_0 ^{30}C_{10}-^{30}C1 ^{30}C_11+...+^{30}C_{20} ^{30}C_{30}[/tex]

Again, I know this is some coeff of the product of some series, but I dont know how to find the series or the coeff.

I dont know how to go about it.