As ( ! C ! ! = = , the formula ! C ! ! is applicable for r = also. Hence ! C ! ! , ≤ r ≤ n . . ! C ! ! n r − = = ( ! ! ! = C r , PERMUTATIONS AND COMBINATIONS i.e., selecting r objects out of n objects is same as rejecting ( n – r ) objects. . n C a = n C b ⇒ a = b or a = n – b, i.e., n = a + b Theorem C C C Proof We have
📖 generic · CBSE Class 11 English medium · MATHEMATICS · Page 160poem
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Chapter 2: 4 P 2 = 4 C 2 ××××× 2! or ( · MATHEMATICS
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