Tool to calculate a linear equation from 2 points. The equation of a line is written ax + b with a, the direction coefficient (or slope) and b, the y-intercept.
Linear Equation - dCode
Tag(s) : Geometry, Functions
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Linear Equation
Linear Equation Calculator (2D plane)
Tool to calculate a linear equation from 2 points. The equation of a line is written ax + b with a, the direction coefficient (or slope) and b, the y-intercept.
Answers to Questions
How to calculate the equations of a line?
A line of the plane (2D) has an equation of the form $ a x + b $, with $ a $ its slope coefficient and $ b $ the y-intercept.
Knowing the slope coefficient and the ordinate at the origin, is deduced the equation of the line.
Example: A line of slope coefficient 2 and intercept 3 has the equation $ 2x + 3 $
How to calculate slope coefficient?
From 2 points $ A(x_A, y_A) $ and $ B(x_B, y_B) $, the formula for the slope coefficient of the line or segment passing through the points A and B is the result of the fraction: $$ \ frac {y2-y1} {x2-x1} $$
Example: A line passes through 2 points A(1,2) and B(3,4), the slope coefficient is $ \frac{4-2}{3-1} = \frac{2}{2} = 1 $
How to calculate the y intercept?
From the slope coefficient $ a $ and a point $ A(x_A, y_A) $, the computation formula of the y-intercept is the result $ b $ of the equation $$ a x_A + b = y_A $$
Example: A line with slope coefficient $ 3 $ goes through A(2,4), so $ 3 \times 2 + b = 4 \iff b = -2 $, so the y intercept is -2
Source code
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