Please help!

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Please help!

by H2O » Tue Jul 15, 2008 9:56 am
# 1 For which of the following functions F is F(x)=F(1-x) for all X?

1. F(x) - 1-x
2. F(x) = 1-x^2
3. F(x) = x^2-(1-x)^2
4. F (x) = x^2(1-x^2)
5. F(x) = x/1-x

The correct answer is 4.

#2 A quarter of a cirlce is drawn. The length of the two straight sides (radii) is 100 each. If the circle is enclosed by a fence, which of the following is closest to the lenght , in feet, of the fence?

Answer is 357.
Source: — Problem Solving |

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by sudhir3127 » Tue Jul 15, 2008 10:04 am
Answer is D

chose the number 2 for x and thus -1 for 1-x only D comes out as correct.

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by H2O » Tue Jul 15, 2008 10:51 am
Can you please explain further. Did you choose 2 at random and why is D correct? Thank you!

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by BlueRain » Tue Jul 15, 2008 10:53 am
H2O wrote:Can you please explain further. Did you choose 2 at random and why is D correct? Thank you!
Just to clarify is choice 4, (1-x^2) or (1-x)^2? If it is the first case, then 4 is incorrect.

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by reachac » Tue Jul 15, 2008 11:06 am
Quater-> length of arc-> (2*pi*r)/4= 314/2= 157 appro

total fence length 100 +100+157=357

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by H2O » Tue Jul 15, 2008 12:39 pm
"Just to clarify is choice 4, (1-x^2) or (1-x)^2? If it is the first case, then 4 is incorrect."

I don't know if wrote down choice D (#4) correctly. It might be x^2(1-x)^2. But I'm still not gettng why that is the correct answer.

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by wilderness » Tue Jul 15, 2008 12:56 pm
Just replace x by 1-x in 4 and you will get back the same expression