How to substitue a function into an equation?



On Fri, 24 Nov 2006, Stavros Macrakis wrote:

> Please tell us more about f(...), x(...), and y(...).
>
>> There is an equation:
>> f(x(t),y(t),z(t))=0
>> I have already get the forms of x(t) and y(t), thus I can get z(t) from
>> the equation above. But I don't know which command I should use. Can
>> somebody tell me?

If $t$ is not explicit in the equation, then you can just solve for $z$ in
  terms of $x, y$ from

$$ f(x,y,z) = 0 $$

e.g., as

  solve(f(x,y,z),z);

-sen

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