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The value of sum(r=2)^(oo) (1+2+....+(r-...

The value of `sum_(r=2)^(oo) (1+2+....+(r-1))/(r!)` is equal to

A

e

B

2e

C

`(e)/(2)`

D

`(3e)/(2)`

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WB JEE PREVIOUS YEAR PAPER-QUESTION PAPER 2012-MULTIPLE CHOICE QUESTIONS
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  2. The sum of series 1+(1)/(2)""^(n)C(1)+(1)/(3)""^(n)C(2)+..... +(1)/(n...

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  3. The value of sum(r=2)^(oo) (1+2+....+(r-1))/(r!) is equal to

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  4. If p=[ {:(1,2,1),(1,3,1):}],Q=P P^(T) then the value of the determina...

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  5. The remainder obtained when 1!+2!+95! is divided by 15is

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  6. If P,Q,R are angles of triangle PQR then the value of |{:(-1, cos R, c...

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  7. The number of real values of alpha for which the system of equations {...

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  8. The total number of injections (one-one into mapping) (from {a(1),a(2)...

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  9. Let (1+x)^10= sum(r=0)^(10)c(r) x^(r), and (1+x)^(7)= sum(r=o)^(7)d(r)...

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  10. Two decks of playing cards are well shuffled and 26 cards are randomly...

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  11. An run contains 9 red and 5 white balls. Three balls are drawn at rand...

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  12. Two coins are available, one fair the other two- headed. Choose a coin...

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  13. Let R be the set of real numbers and the function f: RR to RR and g: R...

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  14. If a,b,c are in arithmetic progression then the roots of the equation ...

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  15. The equation y^(2)+4x+4y+k=0 represents a parabola whose latus rectum ...

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  16. If the circles x^(2)+y^(2)+2x+2ky+6=0 and x^(2)+y^(2)+2ky+k=0 intersec...

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  17. If four distinct points (2k, 3k) (2,0) (0,3) (0,0) lie on a circle, th...

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  18. The line joining A( b cos alpha, b sin alpha) and B( a cos beta, alpha...

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  19. Let the foci of the ellipse (x^(2))/(9)+y^(2)=1 subtend a right angle ...

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  20. The general solution of the differential equation (dy)/(dx)=(x+y+1)/(2...

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