Point Slope or Slope Intercept ? Show
There are a few different ways to write the equation of line .
Point Slope Form is better Point slope form requires fewer steps and fewer calculations overall. This page will explore both approaches. You can click here to see a side by side comparison of the 2 forms.
In the last lesson, I showed you how to get the equation of a line given a point and a slope using the formula
Anytime we need to get the equation of a line, we need two things
ALWAYS! So, what do we do if we are just given two points and no slope? No problem -- we'll just use the two points to pop the slope using this guy:
Check it out: Let's find the equation of the line that passes through the points
This one's a two-stepper... STEP 1: Find the slope
If you're seeing this message, it means we're having trouble loading external resources on our website. If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked. 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:
Also, the text and formulas below the calculators describe how to find the equation of a line from two points manually. Calculation precision Digits after the decimal point: 2 Calculation 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 We need to find slope a and intercept b. For two known points we have two equations in respect to a and b Let's subtract the first from the second
Note that b can be expressed like this So, once we have a, it is easy to calculate b simply by plugging 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 . This vector quantifies the distance and direction of an imaginary motion along a straight line from the first point to the second point. Once we have direction vector from Note that if 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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