# [Maxima] Solve for y when [x=-10, x=10] and d=5

William Porter wmporter.omegapar at comcast.net
Fri Jul 23 12:23:52 CDT 2010

```Solve for y when [x=-10, x=10] and d=5. x and d are input parameters. x will
first be set a value and then d is assigned a value for e1:
x^2+d*y*4+d^2*(-4).

I have the following expression:

(%i1) e1: x^2+d*y*4+d^2*(-4);

2       2

(%o1)                          4 d y + x  - 4 d

(%i2) e2: solve(e1, y);

2        2

x  - 4 d

(%o2)                          [y = - ---------]

4 d

I know that .

(%i3) e3: subst([y=0, d=5], e1);

2

(%o3)                              x  - 100

(%i4) e4: solve(e3, x);

(%o4)                         [x = - 10, x = 10]

(%o3) and (%o4) lines are correct. But I need to assign a value to x for
example x=[-10,10] and d:5 to determine y value. I know that the answer is
y=0. Another example is x=[-50,50] and d:50. I know that the answer is
y=37.5. The problem is I am lost as how to solve this issue.

Can someone help with this issue?

Bill

William Porter

wporter at omegapar.com

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