I want to apply the double angle formula to a simple expression. Here
is an example of what I want to do

>>>f = 2*cos(u)*sin(u)
>>> trigsimp(f)
2*cos(u)*sin(u)

Except I would like trigsimp(f) to be 'sin(2u)'. My specific problem
is finding the max tangential acceleration in a circle when the
velocity is defined by

>>> v = v0*sin(pi*s/s0)

and the tangential acceleration is

>>> at = v*diff(v,s)
pi*v0**2*cos(pi*s/s0)*sin(pi*s/s0)/s0

I then want to apply the double angle formula, because picking the
maximum is as easy as solving sin(u)=1, but this is what I get

>>> at_simp = trigsimp(at)
 pi*v0**2*cos(pi*s/s0)*sin(pi*s/s0)/s0

I tried the TrigSimp() defined in Issue 1181, but it didn't help any.

Also, say I get something working where it will simplify the
expression via the double angle formula and I have x*sin(2*u), but I
know that I want sin(u) to equal 1. Is there any way to extract sin
(2*u) from the expression. The only way I can think of off the top of
my head is to do something like
>>> f = x*sin(2*u)
>>> solve(f.args[1]-1,u)
 [pi/4]
Is this the 'sympy' way of doing it?

Any help comments or suggestions will be appreciated.

Thanks,
Bill

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups 
"sympy" group.
To post to this group, send email to [email protected]
To unsubscribe from this group, send email to [email protected]
For more options, visit this group at http://groups.google.com/group/sympy?hl=en
-~----------~----~----~----~------~----~------~--~---

Reply via email to