The sum of all rational terms in the expansion of (2 15+5 13 )15 is equal to :
- 633
- 6131
- 3133
- 931
Answer
(3) 3133
Solution
Tr+1=15Cr 2 15-r5 5 r3
Rational 5 (15-r) and 3 r r is a multiple of 15 r=0, 15
Sum =15C0 23+15C15 55=8+3125=3133
Answer: (3)
The sum of all rational terms in the expansion of (2 15+5 13 )15 is equal to :
(3) 3133
Tr+1=15Cr 2 15-r5 5 r3
Rational 5 (15-r) and 3 r r is a multiple of 15 r=0, 15
Sum =15C0 23+15C15 55=8+3125=3133
Answer: (3)
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