Piecewise defined functions
- Subject: Piecewise defined functions
- From: Barton Willis
- Date: Fri, 21 Jan 2005 09:53:07 -0600
There is a unit step function in orthopoly; here is a link to the user
documentation and
the source code
http://www.unk.edu/acad/math/people/willisb/orthopoly_doc.html
http://www.unk.edu/acad/math/people/willisb/
(%i1) load("l:/orthopoly-0.94/orthopoly")$
(%i2) unit_step(0);
(%o2) 0
(%i3) unit_step(x);
(%o3) unit_step(x)
(%i4) subst(x=1,%);
(%o4) 1
(%i5) f(x) := (unit_step(x) - unit_step(x-5)) * x;
(%o5) f(x) := (unit_step(x) - unit_step(x - 5)) x
(%i6) f(0);
(%o6) 0
(%i7) f(3/7);
(%o7) 3 / 7
(%i8) f(4.99);
(%o8) 4.99
(%i9) f(4.99b0);
(%o9) 4.99B0
(%i10) f(5);
(%o10) 5
(%i11) f(5.1);
(%o11) 0
(%i12) f(x+y);
(%o12) (y + x) (unit_step(y + x) - unit_step(y + x - 5))
(%i13) plot2d(f(x),[x,-7,7]);
(%o13)
(%i14) assume(a > 5);
(%o14) [a > 5]
(%i15) f(a);
(%o15) 0
(%i16) assume(b > 0, b < 5);
(%o16) [b > 0, b < 5]
(%i17) f(b);
(%o17) b
(%i18)
Barton