msqe-2013 ques 25

[AS]

Suppose f′′(x)/f′ (x) = 1 for all x. Also, f(0) = e^2 and f(1) = e^3.Then integration f(x)dx (-2,2) equals
(A) 2e^2,
(B) e^2 − e^(−2),
(C) e^4 − 1,
(D) None of the above.

[Ankit Agrawal]

Hi,

Since [f''(x)/f'(x)]= 1, f''(x)=f'(x).

Now since f(0)= e^2 and f(1)= e^3, I can safely guess that f(x)= e^(2+x).

Corroborating this guess is the fact that f''(x)=f'(x) when f(x)= e^(2+x).

The next steps will be easy:

1. Integral of e^(2+x) is e^(2+x), i.e., the same.
2. Putting the values (2,-2) on this integral, you get: e^4 - 1

Hence, answer is [c]

[rak]

(c)

[Palash]

I heard that only 6 questions were to be attempted in Paper 2 (Economics).
But i dont remember any such instruction.
Does any one remember clearly?

[IISSII]

YES....IT WAS WRITTEN IN BOLDs ON THE COVER PAGE OF PAPER TWO!!! how many did u do??

[Palash]

I did 5.5 correct ,but they are not the first 6 :(

[Meghanjalli Routh]

You had to do any six out of the ten questions. Not the first six.