Calculus:Help!
posted by Derek
Any ideas on how to solve this: Use a vector solution to show that a scalar equation for the line through the points P1(x1, y1) and P2(x2, y2) is yy1/xx1 = y2y1/x2x1? Very confused as to what is meant by this question. Thanks.

drwls
This just says, correctly, thst the change in y from point (x1,y1) is equal to the slope times the change in x from that point.
The slope of the line is (y2y1)/(x2x1)
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