History of the y-interceptDate: 03/18/2002 at 08:11:37 From: Chris Yang Subject: The history of the y-intercept Why does the variable 'b' represent the y-intercept? I've tried researching it but I can't find the answer. Thank you for your time, Chris Yang Date: 03/18/2002 at 12:34:43 From: Doctor Peterson Subject: Re: The history of the y-intercept Hi, Chris. It is common to write the slope-intercept form as y = mx + b, but that is no more than custom, and perhaps only in America. I suspect that this tradition arose from teaching several different forms of the equation of a line together, so that the same parameter names were used in each. Since one form uses BOTH the x- and y-intercepts, namely x/a + y/b = 1 it was natural to use consecutive letters a and b for the x- and y-intercepts. The "a" disappears in other forms, but the "b" remains. For more about the historical use of the different variables used for Slope, see Jeff Miller's Earliest Uses of Symbols from Geometry: http://jeff560.tripod.com/geometry.html - Doctors Peterson and Sarah, The Math Forum http://mathforum.org/dr.math/ |
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