Tip:A–D to answerE for explanationV for videoS to reveal answer
If ar is the coefficient of x10−r in the Binomial expansion of (1+x)10, then ∑r=110r3(ar−1ar)2 is equal to:
- A.
5445
- B.
3025
- C.
4895
- D.
1210
(Correct Answer)
Explanation
Solution :
Hame pata hai ar=(10−r10)=(r10). Toh ratio hoga:
ar−1ar=r10−r+1=r11−r
Series banegi:
r=1∑10r3(r11−r)2=r=1∑10r(11−r)2
Solve karne par iska sum 1210 aata hai.
Sahi Option: (4)
Explanation
Solution :
Hame pata hai ar=(10−r10)=(r10). Toh ratio hoga:
ar−1ar=r10−r+1=r11−r
Series banegi:
r=1∑10r3(r11−r)2=r=1∑10r(11−r)2
Solve karne par iska sum 1210 aata hai.
Sahi Option: (4)
