vv

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I'd suggest a more difficult conjecture for the next project: any odd number can be written as the difference of a prime number and twice a perfect square.

@Carl Love I think that OP would prefer

eq_arrangement:= (k::posint) -> [k, seq('k+i,k-i', i=1..k-1)];

(maybe also  a local i).

@Hullzie16 The command discont gives the set of discontinuity points. I took the three points (say a,b,c) in the interval 0..5.
The functions were plotted in the intervals  e .. a-e,  a+e .. b-e,  b+e .. c-e,  c+e .. 5-e  (e=0.001) and then displayed together.

@Hullzie16 I took the real parts of the functions. If you want the gaps (to see where the functions have complex values), just remove Re.

@oggsait The equality you want is true only for alpha=1.

@oggsait After expand(simplify(%));  ==>

 

 

restart

assume(0 < alpha, alpha < 1)

fracdiff(t^(3*alpha)/GAMMA(1+3*alpha), t, alpha)

t^(2*alpha)/GAMMA(2*alpha+1)

(1)

simplify(fracdiff(%, t, alpha))

t^alpha/GAMMA(alpha+1)

(2)

 

 

Download fdiff.mw

@dharr It depends on conventions. E,g. in complex analysis, z > 7 means: Im(z) = 0 and Re(z)>7,  but z > 2+3i is not accepted (nonsense).

@nm  Excellent, thanks!

 

restart;

solve(p>=0)   works well, it uses SemiAlgebraic, a very powerful tool.

Note that assuming real is not needed, it is by default; actually, over C a nonconstant polynomial cannot be >=0.

is usually fails, the assume facility is too weak.

 

p4:=expand(add(randpoly([x1,x2,x3,x4,x5],degree=1,homogeneous)^2,1..7));

15414*x1^2+2234*x1*x2+12410*x1*x3-800*x1*x4+6354*x1*x5+16352*x2^2-21950*x2*x3-6182*x2*x4+39096*x2*x5+22603*x3^2-13808*x3*x4-21168*x3*x5+31747*x4^2-33792*x4*x5+35159*x5^2

(1)

solve(p4>=0);

{x1 = x1, x2 = x2, x3 = x3, x4 = x4, x5 = x5}

(2)

Student[Precalculus]:-CompleteSquare(p4,[x1,x2,x3,x4,x5]); # useless
 

35159*(x5-(16896/35159)*x4-(10584/35159)*x3+(19548/35159)*x2+(3177/35159)*x1)^2+31747*(x4-(6904/31747)*x3-(3091/31747)*x2-(400/31747)*x1)^2+22603*(x3-(10975/22603)*x2+(6205/22603)*x1)^2+16352*(x2+(1117/16352)*x1)^2+(250802039/16352)*x1^2-(1/90412)*(-21950*x2+12410*x1)^2-(1/126988)*(-13808*x3-6182*x2-800*x1)^2-(1/140636)*(-33792*x4-21168*x3+39096*x2+6354*x1)^2

(3)

 

 

@Anthrazit Almost. I saw your post and I wanted to answer there, but later I decided to make a separate one, including some code. (Actually I think that your post should have been a question.)

@Carl Love Thank you. Yes, sprintf is definitely easier to read, I should have used it.

- You have alias(f=f(w)) and then D(f)(w). 

- D@@4  is not the same as D^4

- You must be sure that the exprssion you want to substitute appears as a subexpression (e.g. a*b is not subexpression in a*b*c).

@student_1 

int((f_exact(x,t)-f_numeric(x,t))^2, [x=0..2,t=0..2], numeric)^(1/2);

You may want to divide by sqrt(Area) (=2 in this case).

@Federiko On my old computer:

xx:=CodeTools:-Usage(LinearSolve(AA, bb)):
memory used=411.13MiB, alloc change=70.00MiB, cpu time=3.53s, real time=3.43s, gc time=1.22s

(For symbolic computations using floats is usually not a good idea).

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