Hi,
I did test prep 2 and I can't seem to get to the right answer. I tried several things, but I'm not sure I'm 100% of the f(x)=f(x-1) -> does this mean to replace the x values in each equation with x-1?
For which of the following functions f is f(x)=f(1-x) for all x?
A - f(x)=1-x
B - f(x)=1-x^2
C - f(x)=x^2-(1-x)^2
D - f(x)=x^2(1-x)^2
E - f(x)=x/(1-x)
The correct answer is d).
Thanks!
V
GMAT Prep Test 2 - Problem Solving
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- Brent@GMATPrepNow
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Let's try plugging in an easy value for x. How about x = 0.v_schame wrote: For which of the following functions f is f(x)=f(1-x) for all x?
A - f(x)=1-x
B - f(x)=1-x^2
C - f(x)=x^2-(1-x)^2
D - f(x)=x^2(1-x)^2
E - f(x)=x/(1-x)
So, we can reword the question as, For which of the following functions is f(0)=f(1-0)
In other words, we're looking for a function such that f(0) = f(1)
A) f(x)=1-x
f(0)=1-0 = 1
f(1)=1-1 = 0
Since f(0) doesn't equal f(1), eliminate A
B) f(x) = 1 - x^2
f(0) = 1 - 0^2 = 1
f(1) = 1 - 1^2 = 0
Since f(0) doesn't equal f(1), eliminate B
C) f(x) = x^2 - (1-x)^2
f(0) = 0^2 - (1-0)^2 = -1
f(1) = 1^2 - (1-1)^2 = 1
Since f(0) doesn't equal f(1), eliminate C
D) f(x) = x^2(1-x)^2
f(0) = 0^2(1-0)^2 = 0
f(1) = 1^2(1-1)^2 = 0
Since f(0) equals f(1), keep D for now
E) f(x) = x/(1-x)
f(0) = 0/(1-0) = 0
f(1) = 1/(1-1) = undefined
Since f(0) doesn't equal f(1), eliminate E
Since only D satisfies the condition that f(x)=f(1-x) when x=0, the correct answer is D
Cheers,
Brent
- varun289
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v_schame wrote:
For which of the following functions f is f(x)=f(1-x) for all x?
A - f(x)=1-x
B - f(x)=1-x^2
C - f(x)=x^2-(1-x)^2
D - f(x)=x^2(1-x)^2
E - f(x)=x/(1-x)
these type questions are simple but thought - create illusions
put x=1-x in FX u get x=1-x so leave that , A gone
B- (1-x)^2 = make lots of wordy , leave that
c- another wordy forget
D-yes put X =1-x u get same figure as (1-x)^2X^2
Click and move on
simple coollll
For which of the following functions f is f(x)=f(1-x) for all x?
A - f(x)=1-x
B - f(x)=1-x^2
C - f(x)=x^2-(1-x)^2
D - f(x)=x^2(1-x)^2
E - f(x)=x/(1-x)
these type questions are simple but thought - create illusions
put x=1-x in FX u get x=1-x so leave that , A gone
B- (1-x)^2 = make lots of wordy , leave that
c- another wordy forget
D-yes put X =1-x u get same figure as (1-x)^2X^2
Click and move on
simple coollll