Question

In series 1+2+3+..... how many terms would have a sum of 5050 ?​

Answer 1

Answer:

5050=n/2(2a+(n-1)d)

5050=n/2(2+n-1)

5050=n/2(n+1)

2*5050=n^2+n

n^2+n-10100=0

n^2+101n-100n-10100=0

n(n+101)-100(n+101)=0

(n-100)(n+101)=0

n=100

so the no. of terms are 100