Multiple colors in text box
I just found this thread.
I have put together a file (attached) and I want the gradient value in the equation of the tangent line to be a different colour (say, purple), and I also want the y-coordinate of point A to show up in that same other colour - thus emphasising the fact that the exponential function graph has a gradient given by the y-coordinate everywhere on the graph.
I have tried "breaking up" the textboxes by creating other variables, x(A) and y(A), as well as creating a point B, the intersecion of the tangent line with the y-axis, and then defining the variable y(B). Then I have used the latex commands I have found helpful from these posts. The annoying thing is that I cannot get away from the tangent line appearing as y = (m)x + - (y(B)) when the y-intercept is negative. You'll see this in the second file I have uploaded.