Counting & ProbabilityMediumBinomial Theorem, Pascal & Combinatorial Identities ShareBinomial Theorem, Pascal & Combinatorial Identities · Medium problemEvaluate ∑i=215(i2)\displaystyle\sum_{i=2}^{15}\binom{i}{2}i=2∑15(2i).Check Show answer Walk through it step by step Practice more like this Review this concept