Counting & ProbabilityChallengeBinomial Theorem, Pascal & Combinatorial Identities ShareBinomial Theorem, Pascal & Combinatorial Identities · Challenge problemEvaluate ∑k=1n(−1)k−1k(nk)\displaystyle\sum_{k=1}^{n}(-1)^{k-1}k\binom{n}{k}k=1∑n(−1)k−1k(kn) for n≥2n\ge 2n≥2.Check Show answer Walk through it step by step Practice more like this Review this concept