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concept check:parallel to y-axis

Problem Solving — algebra and arithmetic
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Junior | Next Rank: 30 Posts
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by syflysun » Mon Aug 09, 2010 10:53 pm
if line k is parallel to y-axis, then the slope of line k is

A. not defined
B. not existed
C. infinite
D. others?

I know parallel to x, the slope is 0.

thanks
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by KrazyKarl » Mon Aug 09, 2010 11:09 pm
I've always learned slope as: Change in Y / Change in X (rise over run). If x doesn't change, then the denominator is 0, so it would be undefined.
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by arora007 » Wed Aug 11, 2010 9:41 am
y=mx + c

which would mean... if something is parallel to y axis... then x=constant (since x=0 is the Y axis)

y could be anything from 0 to infinity... thus undefined!
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by Maciek » Sat Aug 21, 2010 6:17 am
hi syflysun!

This is example of infinite slope.
Consider the linear function:

y = a + bx

b is the slope of the line. Slope means that a unit change in x, the independent variable will result in a change in y by the amount of b.

slope = change in y/change in x = rise/run
Follow this link to see more details:

https://www.columbia.edu/itc/sipa/math/slope_linear.html

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by Tani » Sat Aug 21, 2010 2:27 pm
The terminology I have always used is an undefined slope. Given slope = change in y over change in x -- if the line is parallel to the y-axis, the change in x is zero. Anything divided by zero is undefined.
Tani Wolff
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