Function questions
Q.1 If f(x) = 9x/ (9x + 3)
Then the value of f(1/160) + f(2/160) + f(3/160) + . . . . . + f(159/160) is
a. 160 b. 76 c. 80 d. 79.5
Q2. If f( x + y) = f(x) f(y) for all real values of x and y, and f(7) = 4, f’(0) = Ln(4/7), then f’(7) = ?
a. 10 b. 4. Ln(4) c. 4. Ln(4/7) d. 20
Q3. If the equation x5 – 10x4 + ax3 + bx2 + cx – 32 = 0 has five positive roots, then a + b + c = ?
a. 80 b. 40 c. 120 d. 30
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Can u xplain ur nswer of the 1st qs...
As, f(x) + f(1-1/x)=1
So, u may get (159/2)=79.5
But as no. of f(x) + f(1-1/x) group cannot be fraction so accordin to me 80 may be the correct one..
Plz xplain ur process...
THNKZ IN ADVANCE
Regards,
Dipanjan.....
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Q.1 If f(x) = 9x/ (9x + 3)
Then the value of f(1/160) + f(2/160) + f(3/160) + . . . . . + f(159/160) is
a. 160 b. 76 c. 80 d. 79.5
Sol. f(x) = 9x/ (9x + 3)
f(1 - x) = 91-x/(91-x +3)
f(x) + f(1 - x) = 1.
f(1/160) + f(159/160) = 1, f(2/160) + f(158/160) = 1, .............................................
............................................... and f(79/160) + f(81/160) = 1, f(80/160) = 1/2
Ans. 79.5
Q.1 If f(x) = 9x/ (9x + 3)
Then the value of f(1/160) + f(2/160) + f(3/160) + . . . . . + f(159/160) is
a. 160 b. 76 c. 80 d. 79.5
I got (c) 80 as answer...
GIV YOUR BEST TO THE WORLD...
AND THE BEST WILL COME BACK TO U.....
Regards,
Dipanjan.....
n/a
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