Autograph Forums

Hello,

I am using the function definition facility e.g.

f(x) = e^(x/2)
g(x) = 3x - 1

to graph expressions such as

y = f(2x), y = f(x +2), y= gf(x) = g(f(x)) etc.

If I click on both graphs then right-click I can use the "Solve f(x) = g(x)" option to find the point of intersection of the displayed curves , not the "underlying" functions. That is great.

I can graph the "inverse" functions (obviously not all graphs strictly have inverses) using the reflect button. Good.

However, if I select the two reflections (or just one reflection and one other graph), the "Solve f(x) = g(x)" option is not available in the menu. Therefore I can't graphicaly solve equations such as

f(x) = g-1(x)

Can this option be added or is there another way to do this? (without working out the inverse function by hand)

Thanks

Clive

Dear Clive,

I have been playing with this this morning and can confirm that I get the same behaviour as you. Unfortunately reflections are not treated as "first-class" functions and therefore we do not have the option for solving intersections.

I have also tried plotting x = g(y), which of course plots correctly but also does not allow us to solve intersections.

We can definitely add this to the feature request list but for the time being you will need to resort to calculating the inverse manually.

Thank you for bringing this to our attention.

Best regards,

Simon