Hi everybody,
Some arguments of a user-defined function can be functions:
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C1) double(f,a):=2*f(2*a);
(D1) double(f, a) := 2 f(2 a)
(C2) double(sin,%pi/3);
(D2) SQRT(3)
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A function can be defined as the derivative of another one:
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(C3) sin2x2(x):=2*sin(x2);
2
(D3) sin2x2(x) := 2 SIN(x )
(C4) df(x):=''(diff(sin2x2(x),x));
2
(D4) df(x) := 4 x COS(x )
(C5) df(3);
(D5) 12 COS(9)
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The previous construction can be used in the definition of a function:
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(C6) N(a):=block(dg(x):=''(diff(sin2x2(x),x)),dg(2*a));
2
(D6) N(a) := BLOCK(dg(x) := 4 x COS(x ), dg(2 a))
(C7) N(3);
(D7) 24 COS(36)
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So i don't understand why this does not work:
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(C8) Nf(f,a):=block(fd(x):=''(diff(f(x),x)),fd(a+5));
d
(D8) Nf(f, a) := BLOCK(fd(x) := -- (f(x)), fd(a + 5))
dx
(C9) Nf(sin,3);
Attempt to differentiate with respect to a number:
8
#0: fd(x=8)
#1: Nf(f=SIN,a=3)
-- an error. Quitting. To debug this try DEBUGMODE(TRUE);)
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Can anybody give me the correct syntax.
Thanks in advance,
JDF