Posted: 3/17/2010 10:05:03 AM EDT
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I'm finishing up some studying before my Math class tonight. I am reviewing notes but don't know what I did with this one section. Essentially I have the problem : f(x)=x^2-25. Which factored yields x=-5, or 5. I labeled the key point, 5, -5, and -25 for the vertex. It asks me if it is a one to one function. From my understanding a one to one function is one that passes the horizontal and or the vertical line test. My answer says that the function is not a one to one function. Then we move onto the inverse of the function. -5,0) 5,0), AND 0,25). This also gets a little bit murky for me as the inverse flips it over correct, so just reverse the points?
Thanks a bunch! 
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Also, I have the problem. y=5-2x. It asks for the inverse, so I add five to both sides, getting 2x=5+y. Dividing by two I get. x=5+y/2. Is this the inverse? Wouldn't adding 5 to both sides equal y+5=10-2x? Then dividing by 2 gets you (y+5)/2=5-x? It's been a looooooooooong time since I've done this, so I'm probably wrong. |
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Also, I have the problem. y=5-2x. It asks for the inverse, so I add five to both sides, getting 2x=5+y. Dividing by two I get. x=5+y/2. Is this the inverse? Wouldn't adding 5 to both sides equal y+5=10-2x? Then dividing by 2 gets you (y+5)/2=5-x? It's been a looooooooooong time since I've done this, so I'm probably wrong. Well, I do have notes from the class but am doing the last bit of studying before my 6pm math class final. See what gets me is this. I tried it again I tried it like this: x=5-2y -5 x-5=-2y/-2 which yields x+5/2=y. Now the inverse is the opposite of the answer for the given variable if I am not mistaken, running through some internet tutorials but it isn't working the greatest, because I am confused about this last portion. |
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Quoted: Also, I have the problem. y=5-2x. It asks for the inverse, so I add five to both sides, getting 2x=5+y. Dividing by two I get. x=5+y/2. Is this the inverse? If you have y=5-2x then you need to subtract 5 from both sides, which gives you y-5=-2x, then divide by -2, (y-5)/-2=x |
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Spoiler: x = (5-y)/2 ETA: I think.... So much for engineering school. Haha lucky for me I have no interest in engineering. Know an older naval fellow, he said the engineers have the personallity and social skills of a wet mop. Laugh every time I think about it haha. But why is it not x=5+y/2? Heres my math for that way. 2x=5+y. Divide by 2 yields, x=5+y/2? This results from the initial y=5-2x. So I add 5 to both sides. getting me 5+y= 2x. Division by two gets me the answer, I posted. |
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Also, I have the problem. y=5-2x. It asks for the inverse, so I add five to both sides, getting 2x=5+y. Dividing by two I get. x=5+y/2. Is this the inverse? Wouldn't adding 5 to both sides equal y+5=10-2x? Then dividing by 2 gets you (y+5)/2=5-x? It's been a looooooooooong time since I've done this, so I'm probably wrong. Well, I do have notes from the class but am doing the last bit of studying before my 6pm math class final. See what gets me is this. I tried it again I tried it like this: x=5-2y -5 x-5=-2y/-2 which yields x+5/2=y. Now the inverse is the opposite of the answer for the given variable if I am not mistaken, running through some internet tutorials but it isn't working the greatest, because I am confused about this last portion. (x-5)/-2 does not equal (x+5)/2. It would, if anything, equal -(x-5)/2. ETA: Let's walk through this (I can't remember how to work the first problem, so we'll skip that): x=5-2y Subtract 5 from both sides. x-5=-2y Divide both sides by -2. (x-5)/-2=y OR -(x-5)/2=y. Say x=19. (19-5)/-2=y 14/-2=y -7=y |
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Also, I have the problem. y=5-2x. It asks for the inverse, so I add five to both sides, getting 2x=5+y. Dividing by two I get. x=5+y/2. Is this the inverse? If you have y=5-2x then you need to subtract 5 from both sides, which gives you y-5=-2x, then divide by -2, (y-5)/-2=x I tried it your way. I get x=5-y/-2, which turns the 5 to negative and y to postitive. Yielding 5-y/2=x? |
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Also, I have the problem. y=5-2x. It asks for the inverse, so I add five to both sides, getting 2x=5+y. Dividing by two I get. x=5+y/2. Is this the inverse? Wouldn't adding 5 to both sides equal y+5=10-2x? Then dividing by 2 gets you (y+5)/2=5-x? It's been a looooooooooong time since I've done this, so I'm probably wrong. Well, I do have notes from the class but am doing the last bit of studying before my 6pm math class final. See what gets me is this. I tried it again I tried it like this: x=5-2y -5 x-5=-2y/-2 which yields x+5/2=y. Now the inverse is the opposite of the answer for the given variable if I am not mistaken, running through some internet tutorials but it isn't working the greatest, because I am confused about this last portion. (x-5)/-2 does not equal (x+5)/2. It would, if anything, equal -(x-5)/2. This part is confusing here. I realize that the x would become negative, then the -5 would become positive and so would the -2. Yielding, -x+5/2=y. |
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Quoted: Quoted: Quoted: Also, I have the problem. y=5-2x. It asks for the inverse, so I add five to both sides, getting 2x=5+y. Dividing by two I get. x=5+y/2. Is this the inverse? If you have y=5-2x then you need to subtract 5 from both sides, which gives you y-5=-2x, then divide by -2, (y-5)/-2=x I tried it your way. I get x=5-y/-2, which turns the 5 to negative and y to postitive. Yielding 5-y/2=x? You have to divide each part of it by -2. -(y/2)+(5/2)=x |
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y=5-2x
Subtract 5 from each side y-5=-2x Divide each side by 2 (y-5)/2=-x Multiply both sides by -1 to simplify (5-y)/2=x or x=(5-y)/2 ETA: sd_norske beat me to it. Good to know I still got it, though. Now I just have to deal with that "wet mop" personality of mine... |