# Inputting 3 piecewise functions in one f(x)???

menonn shared this question 3 years ago

I am trying to do a Solid of Revolution about the x-axis with 3 functions creating my enclosed area, like this:

However when I put it into geobra

f(x) = If[0.22 ≤ x ≤ 1.087, ℯ^x / 2, If[1.087 ≤ x ≤ 1.794, acos(x - 1),If[0.22 ≤ x ≤ 1.794, 1 - sqrt(3 / 4 - (x - 1)²)]]]

It only prints out the top two functions and not the bottom one. I need all three in one f(x) because I'm using this template: https://www.geogebra.org/m/HPTaQb4w

Here's what I'm getting in GeoBra:

The last function, the half-circle is not printing out. This is for a Calc project.

And here's what it should look like:

1

your f is not a function

you can create two surfaces: one for f one for g

in other case you must use a curve

1

First of all, as @mathmagic explains f(x) is not a function.

On the other hand your definition of f(x) is not correct. Third argument "If[0.22 ≤ x ≤ 1.794 ...]" will never be executed because if your main IF tries to execute this sentence it is because "0.22 ≤ x ≤ 1.087" and "1.087 ≤ x ≤ 1.794" are both false.

See help for if command: https://wiki.geogebra.org/e...

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