Piecewise

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Siper

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Apr 2, 2001, 7:11:41 PM4/2/01
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Does anyone know how to enter a piecewise function like you can on a TI?

something like f(x) = x^2 |x<0

--

Micah

Rob Atkinson

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Apr 2, 2001, 8:59:39 PM4/2/01
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There are a number of ways depending on what you are using the function for.

You can put it in a program << -> X << X 0. < 'X^2' 0. IFTE >> >> or under
the graph menu, you can specify the limits of the independant variable
aswell. Do you have any specific examples?

- Rob

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Alan Kenneth Oquendo

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Apr 2, 2001, 10:06:33 PM4/2/01
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There's an easier way than that, which I found back in my glory days of high
school (man it's only been two years since then and already I feel I could
attend my 10 year reunion). But anyway, let's say you wanted to make a
piecewise function such as

f(x) = x, 0 < x < pi/2;
f(x) = (pi/2) sin(x), x > pi/2.

then what you can do is simply multiply each part by the given range and
then add them, so if you put this into the equation editor it would like so

Y1(X) = X*(0<X<pi/2) + (pi/2)*SIN(X)*(X>pi/2)

For your case, all you need to do is put down

Y1(X) = X^2*(X<0)

but I thought I'd include a larger example in case you run into more
complicated piecewise functions later on.

Cheers,
Alan Oquendo '03
aoqu...@princeton.edu


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Virgil

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Apr 2, 2001, 11:07:07 PM4/2/01
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In article <NG7y6.21681$ea6.2...@news1.frmt1.sfba.home.com>,
"Siper" <nos...@yahoo.com> wrote:

You can use the IFTE function (IFTE means IF Then Else):
'IFTE(condition, value_if_true,value_if_false)'

'F(X) = IFTE(X==0,0,SIN(X)/X)' DEFINE
or
'G(X) = IFTE(X<0,0,IFTE(X<1,X,X^2))' DEFINE

Virgil

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Apr 3, 2001, 1:33:13 AM4/3/01
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In article <9abarr$p84$1...@cnn.Princeton.EDU>,

"Alan Kenneth Oquendo" <aoqu...@princeton.edu> wrote:

> There's an easier way than that, which I found back in my glory days of high
> school (man it's only been two years since then and already I feel I could
> attend my 10 year reunion). But anyway, let's say you wanted to make a
> piecewise function such as
>
> f(x) = x, 0 < x < pi/2;
> f(x) = (pi/2) sin(x), x > pi/2.
>
> then what you can do is simply multiply each part by the given range and
> then add them, so if you put this into the equation editor it would like so
>
> Y1(X) = X*(0<X<pi/2) + (pi/2)*SIN(X)*(X>pi/2)

The above will not work as expected on HPs, it needs to be

'Y1(X) = X*(0<X)*(X<pi/2) + (pi/2)*SIN(X)*(X>pi/2)'

Alan Kenneth Oquendo

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Apr 3, 2001, 7:30:13 AM4/3/01
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Oh wow, thanks Virgil! That helps me too :-)

Cheers,
Alan Oquendo '03
aoqu...@princeton.edu


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