multiline functions that I can then plot

[woym]

I've written a multiline function using LaTex, but then I can't seem to work out how to plot it.

f(x) = \begin{cases} \frac{12}{7}(1+x)^2 & \quad \text{for} \; -1< x \leq 0\\ \frac{12}{7}(1-x)^3 & \quad \text{for} \; 0< x < 1\\ 0 & \quad \text{otherwise} \end{cases}

I don't know where to go from here!
Any help is greatly appreciated.
Thank you

[woym]

Thank you so much for the response. I'm just trying to plot the function for the different values of x as you've mentioned. I just don't know how to do it for multiline functions like the one in this case. Especially with the differing domains.

Your help is greatly appreciated.

[Yarnabrina]

@woym

Especially with the differing domains.

Are you new to programming? In this situations, the if - else if - else is almost always the most obvious solution. Add the first case under if, and in case there are more, add those conditions one by one under else if. If all the cases are collectively exhaustive, you can use else in the final one, as there's only one possibility left.

See below:

f <- function(x)
{
  if ((-1 < x) & (x <= 0))
  {
    return((12 / 7) * ((1 + x) ^ 2))
  } else if ((0 < x) & (x < 1))
  {
    return((12 / 7) * ((1 + x) ^ 3))
  } else
  {
    return(0)
  }
}

x_vals <- seq(from = -2,
              to = 2,
              by = 0.01)

y_vals <- sapply(X = x_vals,
                 FUN = f)

plot(x = x_vals,
     y = y_vals)

^{Created on 2019-04-01 by the reprex package (v0.2.1)}

I didn't join the points, you can do that by specifying type="l". Hope this helps.

PS I'm changing the category of your post, as it doesn't relate to either R Markdown or latex. Hope you don't mind.

PPS You can write LaTeX equations within a pair of $$ in R markdown. Check my edit in the question.