## 545 Reputation

16 years, 49 days

I've been using Maple since 1997 or so.

## Look at your Sum or sum...

Look at your Sum or sum command. n1 is being summed from n to n-1 and you are asking for a closed form for maple to then work with. There is probably not a closed form for maple to work with. Sum or sum returns the un-evaluated form and can't finish to other operations on that un-evaluated form. marvinrayburns.com searchme! Marvin Ray Burns My Desire

## test...

5 < 6 D(14) should and does give you an integer. However, what does D(2*U) give, where U has not been defined?

## Here is a my way...

That is actually an old problem from the Maple 5 programming guide. However, here is my routine. Simply change the form of p and the if statement, to match your variables. With a little foresight, this can be automatically done in a program. You can also improve the if statement to "factor out" common multiples of the coeff. ``` > p := 3*x+3*y+3*z: > if coeff(p,x)=coeff(p,y)and coeff(p,x)=coeff(p,z) then printf("%a*(x+y+z)",coeff(p,x)) else printf("%a",p) end if; 3*(x+y+z) > p := 3*x+3*y: > if coeff(p,x)=coeff(p,y) then printf("%a*(x+y)",coeff(p,x)) else printf("%a",p) end if; 3*(x+y) > p := 1*x+3*y+3*z: > if coeff(p,x)=coeff(p,y)and coeff(p,x)=coeff(p,z) then printf("%a*(x+y+z)",coeff(p,x)) else printf("%a",p) end if; x+3*y+3*z ```

My Desire
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