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I don't understand how to do these. With the last one, I graphed each function but they all looked symmetric. Please help and show how to solve these. Thanks!

 Oct 23, 2019
 #1
avatar+109563 
+1

The first one is a little tricky, but not that hard if we just think about it

 

The total perimeter  = 2 (70 + 50)  = 2 * 120  = 240  m

 

The point (0, 0)  is one point on the graph.....at 0 minutes we have walked  0  m   !!!

 

Also.....if the person walks for three minutes......he has walked 3(80m)  = 240  m = 1 round

 

So....he has made  1 round in 3 minutes

 

So....the point  ( 3,1)   should be on the graph 

 

So.....the graph at the bottom left  is the correct one 

 

Note that  after  6 minutes, we have made 2 rounds

 

So.....(6,2)  is also on the graph

 

 

cool cool cool

 Oct 23, 2019
 #2
avatar+109563 
+1

If the graph is symmetric with the y axis....it is an even function which means that

 

[Symmetric with y means that we can fold the graph over the the y axis and it will lay on top of itself ] 

 

f(x)  = f(-x)

 

Look at A

 

f(x)  =  4 - x^2

 

f(-x)  =  4 - (-x)^2   =   4 - x^2

 

Since f(x)  = f(-x)......this is the one that is symmetric withthe  y axis

 

See the graph here :  https://www.desmos.com/calculator/trwnp3rhxf

 

 

cool cool cool

 Oct 23, 2019
 #3
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+1

Oh okay! I was thinking symmetric was something different. Thank you so much.

Guest Oct 23, 2019

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