solve and calculate

Question

How can I solave an equation like x+z^2=1 and then calculate x with z=3 from the solution?

Thanks.

Accepted Answer

1

z=var('z')
solve(x+z^2==1,x)[0].substitute(z==3)

posted Jan 26 '12

1580 ● 6 ● 22 ● 55

This works, but is there also a more comfortable way to write this:

solve(energiebilanz, h51x)[0].substitute(c_luft=12m/s, mw=(1/3600)kg/s, hw=146.68J/g, TL=313K)

maybe like in a set of parameters?

Thanks.

Mebus (Jan 27 '12)

This works, but is there also a more comfortable way to write this:

solve(energiebilanz, h51x)[0].substitute(c_luft=12m/s, mw=(1/3600)kg/s, hw=146.68J/g, TL=313K)

Mebus (Jan 27 '12)

Answer 2

A variation on the Shashank'answer :

sage: z=var('z')
sage: f(z)=solve(x+z^2==1,x)[0].rhs()
sage: f
z |--> -z^2 + 1
sage: f.diff(z)
z |--> -2*z
sage: f.plot()

Here you consider the function "solution of the equation as function of z", and you do whatever with it.

2 Answers: