Posted by Subhotosh Khan on October 07, 2002 at 12:10:31:
In Reply to: distance formula posted by Robert Mulder on October 07, 2002 at 11:58:24:
: I need the formula for the following:
: Given point A, distance, and slope -> find the location of point B.
: I realize that there are actually two points...I need both.
: Thanks,
: Robert
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Assume co-ordinates of point A (x_a,y_a) and co-ordinated of point B is (x_b,y_b)
1) Slope of line AB
(y_b-y_a)/(x_b-x_a) = m ..............(1)
2) Length of line AB
d^2 = (x_b - x_a)^2 + (y_b - y_a)^2
= (x_b - x_a)^2 + m^2 * (x_b - x_a)^2
= (x_b - x_a)^2 (1+ m^2 )
So
(x_b - x_a)^2 =d^2/(1+ m^2 ) ..........(2)
From (2) you can find two values of x_b. Then use (1) to get two values of y_b