I know this is really basic, but for some reason I cannot figure this
out and my searching (here, sage website, google, etc) has not yielded
me any results! I just started using sage, literally, yesterday.
I am using solve() to solve an equation for q1 in terms of q2. The
solution of this is saved, but when I print it, it prints as an exact
answer, but I want it in decimal/approximate form. I have tried using
the n() function, but I get an error when trying it.
Here is an example:
--------------------------------------------------
q1, q2 = var('q1, q2')
r = 0.60
t1 = 0.005
t2 = 0.007
d = 2.0
A1 = (1/2)*pi*r*r
A2 = (1/2)*d*(2*r)
theta1 = 1/(2*A1)*(q1*2*pi*r/t1+(q1-q2)*2*r/t1)
theta2 = 1/(2*A2)*(q2*d/t2+q2*sqrt(d^2+(2*r)^2)/t2+(q2-q1)*2*r/t1)
sol_q1 = solve([theta1==theta2], q1)
print sol_q1
print sol_q1[0].substitute(q2=1).right().n()
--------------------------------------------------
When this is run, the result for sol_q1 is: q1 = (223317 pi + 416000)/
((223317 pi + 416000) q2)*q2
The last line does work to give me the desired value (0.58239....),
but this is definitely not an ideal way of getting it! And of course
this wouldn't work for a more complicated result (since I use q2=1).
I've tried many other combinations of sol_q1.n(), sol_q1[0].n(), etc,
etc, etc...but they all give me errors. As a note:
sol_q1 is a Sequence (list of the answers)
sol_q1[0] is a SymbolicEquation
Thanks for the help,
Scott
PS: I tried using the for loop a little more than half way down on
this page:
<http://www.sagemath.org/doc/reference/sage/symbolic/relation.html>
but my solution are functions of q2, not numbers, so it fails.
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