1.

If `lim_(xrarr1)(x+x^2+x^3+....+x^n-n)/(x-1)=5050` , then `n=`A. 10B. 100C. 150D. none of these

Answer» Correct Answer - B
We have,
`lim_(x to oo) (x+x^2+x^3+....+x^n-n)/(x-1)=5050`
`rArr (n(n+1))/(2)=5050 ["See illustration" 3]`
`rArr n=100`


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