quadratic.Rmd

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Given the quadratic formula:

$x = \frac{-b \pm \sqrt{b^2 -4ac}}{2a}$

Formatted in an R Markdown document as follows:

    $x = \frac{-b \pm \sqrt{b^2 -4ac}}{2a}$

We can substitute the following values:

$a = `r# x(v$formula$quadratic$a)`, b = `r# x(v$formula$quadratic$b)`, c = `r# x(v$formula$quadratic$c)`$

`r# -x(v$formula$quadratic$b) + sqrt( v$formula$quadratic$b^2  - 4 * v$formula$quadratic$a * v$formula$quadratic$c )`

To arrive at two solutions:

$x = \frac{-b + \sqrt{b^2 -4ac}}{2a} = `r# (-x(v$formula$quadratic$b) + sqrt( x(v$formula$quadratic$b)^2  - 4 * x(v$formula$quadratic$a) * x(v$formula$quadratic$c) )) / (2 * x(v$formula$quadratic$a))`$

$x = \frac{-b - \sqrt{b^2 -4ac}}{2a} = `r# (-x(v$formula$quadratic$b) - sqrt( x(v$formula$quadratic$b)^2  - 4 * x(v$formula$quadratic$a) * x(v$formula$quadratic$c) )) / (2 * x(v$formula$quadratic$a))`$

Changing the variable values is reflected in the output immediately.