You can find an equation of a straight line given two points laying on that line. However, there exist different forms for a line equation. Here you can find two calculators for an equation of a line: Show
Also, the text and formulas below the calculators describe how to find the equation of a line from two points manually. Slope-intercept line equation from two pointsFirst PointSecond pointCalculation precision Digits after the decimal point: 2 Parametric line equation from two pointsFirst PointSecond pointCalculation precision Digits after the decimal point: 2 How to find the equation of a line in slope-intercept formLet's find slope-intercept form of a line equation from the two known points and . Let's subtract the first from the second Note that b can be expressed like this Finally, we use the calculated a and b to write the result as Equation of a vertical lineNote that in the case of a vertical line, the slope and the intercept are undefined because the line runs parallel to the y-axis. The line equation, in this case, becomes Equation of a horizontal lineNote that in the case of a horizontal line, the slope is zero and the intercept is equal to the y-coordinate of points because the line runs parallel to the x-axis. The line equation, in this case, becomes How to find the slope-intercept equation of a line exampleProblem: Find the equation
of a line in the slope-intercept form given points (-1, 1) and (2, 4)
And here is how you should enter this problem into the calculator above: slope-intercept line equation example Parametric line equationsLet's find out parametric form of a line equation from the two known points and . Once we have
direction vector from to , our parametric equations will be Equation of a vertical lineNote that in the case of a vertical line, the horizontal displacement is zero because the line runs parallel to the y-axis. The line equations,
in this case, become Equation of a horizontal lineNote that in the case of a horizontal line, the vertical displacement is zero because the line runs parallel to the x-axis. The line equations, in this case, become How to find the parametric equation of a line exampleProblem: Find the equation of a line in the parametric form given points (-1, 1) and (2, 4)
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