(1) Why do you have a coefficient of 2.5 in f[u,v], instead of 5/2? This is making Mma do everything in terms of numerical approximations instead of exact solutions. Is that your intent? (2) "All I wanted was for it to square the expression for f[u,v] here" -- try Expand[ f[u,v]^2 ]. --Michael On Fri, May 13, 2011 at 3:34 PM, Dan Asimov <dasimov@earthlink.net> wrote:

Why Mathematica drives me up the wall:

All I wanted was for it to square the expression for f[u,v] here.

Finally (after the following) I tried Expand first, then Simplify, and at last it actually squared the thing. Sheesh.

--Dan

****************************************************************** In[1]:= f[u_,v_] := Sqrt[5+4Cos[u]] + 2.5*Sin[(u-v)/2] + Sqrt[11-6Cos[v]-2Sin[v]]

In[2]:= g[u_,v_] := f[u,v]^2

In[3]:= g[u,v]

u - v Out[3]= Power[Sqrt[5 + 4 Cos[u]] + 2.5 Sin[-----] + 2

...

Sqrt[11 - 6 Cos[v] - 2 Sin[v]], 2]

In[4]:= FullSimplify[g[u,v]]

u - v Out[4]= Power[Sqrt[5 + 4 Cos[u]] + 2.5 Sin[-----] + 2

...

Sqrt[11 - 6 Cos[v] - 2 Sin[v]], 2]

In[5]:= Clear[g]

In[6]:= g[u_,v_] := f[u,v]*f[u,v]

In[7]:= g[u,v]

u - v Out[7]= Power[Sqrt[5 + 4 Cos[u]] + 2.5 Sin[-----] + 2

...

Sqrt[11 - 6 Cos[v] - 2 Sin[v]], 2]

In[8]:= Simplify[%]

u - v Out[8]= Power[Sqrt[5 + 4 Cos[u]] + 2.5 Sin[-----] + 2

...

Sqrt[11 - 6 Cos[v] - 2 Sin[v]], 2]

In[9]:= In[9]:= (Sqrt[5+4Cos[u]] + 2.5*Sin[(u-v)/2] + Sqrt[11-6Cos[v]-2Sin[v]])*(Sqrt[5+4Cos[u]] + 2.5*Sin[(u-v)/2] + Sqrt[11-6Cos[v]-2Sin[v]])

u - v Out[9]= Power[Sqrt[5 + 4 Cos[u]] + 2.5 Sin[-----] + 2

...

Sqrt[11 - 6 Cos[v] - 2 Sin[v]], 2]

In[10]:= Simplify[%]

u - v Out[10]= (Sqrt[5 + 4 Cos[u]] + 2.5 Sin[-----] + 2

2

...

Sqrt[11 - 6 Cos[v] - 2 Sin[v]])

******************************************************************

Sometimes the brain has a mind of its own.

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