Alfred_F

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These are questions asked by Alfred_F

Having started learning Maple about a year ago as a beginner, and now having mastered my preferred area of ​​"ordinary differential equations" fairly independently, I'd like to explore "elliptic curves" in Maple. For practice, I've chosen two problems, for each of which I only know one solution:

y^2 = x^3  -51*x^2 + 867*x - 4792    (17;11)

y^2 - 2*y + 14 = 2*x^3 + 11*x^2 - 29*x - 17    (3;7)


My attempts using commands like "algcurves", "ThueSolve", and "parametrization" have failed. How does one approach such problems in Maple? I'm also particularly interested in the group-theoretically based graphical secant method.

(I'm familiar with the book by Silverman/Tate.)

We are looking for the smallest natural number n with the property that both the digit sum Q(n) of the number n and the digit sum Q(n + 1) of the successor of n are divisible by 5.

During a birthday party, the birthday child realizes: In 1968, I was the same age as the sum of the digits of my birth year. How old will I be now at the end of 2025?

(Please no AI solution)

In the decimal system, specify the smallest natural number k that begins with the digit 7 and has the following additional property:
If you delete the first digit 7 and write it at the end, the newly created number z = (1/3)*k.

I would like to experiment with error estimation in the symbolic solution of ordinary differential equations. I've written a simple example in the attached file. I would now like to plot both the left side of the ODE and the solution y(x) together in the same coordinate system. I can't do this, and I'm asking for help. How can the cumbersome numerical terms in the solution y(x) be converted to floating-point numbers?

As I said, this is a recreational experiment ;-) .DGL_test.mw

restart

ode := x^2 = sum(x*(diff(y(x), [`$`(x, i)]))/factorial(i), i = 0 .. 3)

x^2 = x*y(x)+x*(diff(y(x), x))+(1/2)*x*(diff(diff(y(x), x), x))+(1/6)*x*(diff(diff(diff(y(x), x), x), x))

(1)

``

``

ics := y(0) = 0, (D(y))(0) = 0, ((D@@2)(y))(0) = 0

y(0) = 0, (D(y))(0) = 0, ((D@@2)(y))(0) = 0

(2)

dsolve({ics, ode})

y(x) = x-1+((1/12)*(2-2^(1/2))*(1+2^(1/2))^(2/3)+(1/12)*2^(1/2)*(1+2^(1/2))^(1/3)+1/3)*exp(((1+2^(1/2))^(2/3)*2^(1/2)-(1+2^(1/2))^(2/3)-(1+2^(1/2))^(1/3)-1)*x)+((1/12)*(2^(1/2)-2)*(1+2^(1/2))^(2/3)-(1/12)*2^(1/2)*(1+2^(1/2))^(1/3)+2/3)*exp(-(1/2)*((1+2^(1/2))^(2/3)*2^(1/2)-(1+2^(1/2))^(2/3)-(1+2^(1/2))^(1/3)+2)*x)*cos((1/2)*3^(1/2)*(1+2^(1/2))^(1/3)*(2^(1/2)*(1+2^(1/2))^(1/3)-(1+2^(1/2))^(1/3)+1)*x)-3^(1/2)*(-1+(2^(1/2)-1)*(1+2^(1/2))^(1/3))*2^(1/2)*exp(-(1/2)*((1+2^(1/2))^(2/3)*2^(1/2)-(1+2^(1/2))^(2/3)-(1+2^(1/2))^(1/3)+2)*x)*sin((1/2)*3^(1/2)*(1+2^(1/2))^(1/3)*(2^(1/2)*(1+2^(1/2))^(1/3)-(1+2^(1/2))^(1/3)+1)*x)/((1+2^(1/2))^(2/3)*(12*2^(1/2)-12))

(3)

NULL``

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