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● Determine n if 2nc2" nc2-12:1Find a if the 1 7th and 18th terms of the following expansion are equal: (2+ a)SIn an 4.P the first term is 2 and the sum of the first five terms is one fourth of t50 |
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Answer» (2+a)^50=(a+2)^5017th term=18th term50C17*a^17*2^33=50C18*a^18*2^32so a=50C17*2/50C18a=(50!/33!*17! *2)/(50!/32!*18!)so a=2*32!*18*17!/(33*32!*17!)so a=2*18/33=36/33=12/11 |
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