The equation of a straight line with gradient m and passes through a point (x1, y1) is
y - y1 = m(x - x1)
Thanks in advance.
Can somebody prove y - y1 = m(x - x1) ?
2018-03-12 8:05 pm
回答 (2)
2018-03-12 8:38 pm
✔ 最佳答案
Consider a point (x, y) which is a point on the straight line, and m is the slope of the straight line.By definition: m = Δy / Δx
Then, m = (y - y₁) / (x - x₁)
Hence, y - y₁ = m (x - x₁)
2018-03-12 8:33 pm
general equation of a straight line is y = mx + C
or C = y – mx
y₁ = mx₁ + C
C = y₁ – mx₁ = y – mx
y – y₁ = m(x – x₁)
or C = y – mx
y₁ = mx₁ + C
C = y₁ – mx₁ = y – mx
y – y₁ = m(x – x₁)
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