## write degrees?...

I have functions with sin(x) and  cos(x) terms with x values are degrees.

How to calculate sin(30 degree)?

How to insert degree symbol in maple?

Suppose evaluate  sin(Pi/2), my out put becomes sin(Pi/2)...How to solve this problem?

## idea for trigonometric animation in Maple ?...

Hi,

Idea for trigonometric animation like this? Thanks

## Please need help with my proc...

Please I need help with my proc.

> RK2skritt:=proc(FR::procedure,xo,yo,vxo,vyo,h) local x, y, vx, vy, r, kx1, kx2, kx3, kx4, ky1, ky2, ky3, ky4, l x1, l x2, l x3, l x4, ly1, ly2, ly3, ly4, tmp; r:=sqrt(xo*xo+yo*yo); tmp:=-(h*FR(r))/(r); lx1:=h*vxo; ly1:=h*vyo; kx1:=tmp*xo; ky1:=tmp*yo; lx2:=h*(vxo+0.5*kx1); ly2:=h*(vyo+0.5 ky1); r:=sqrt((xo+0.5*lx1)^(2)+(yo+0.5*ly1)^(2)); tmp:=-(h*FR(r))/(r); kx2:=tmp*(xo+0.5*lx1); ky2:=tmp*(yo+0.5*ly1); lx3:=h*(vxo+0.5*kx2); ly3:=h*(vyo+0.5*ky2); r:=sqrt((xo+0.5*lx2)^(2)+(yo+0.5*ly2)^(2)); tmp:=-(h*FR(r))/(r); kx3:=tmp*(xo+0.5*lx2); ky3:=tmp*(yo+0.5*ly2); lx4:=h*(vxo+kx3); ly4:=h*(vyo+ky3); r:=sqrt((xo+lx3)^(2)+(yo+ly3)^(2)); tmp:=-(h*FR(r))/(r); kx4:=tmp*(xo+lx3); ky4:=tmp(yo+ly3); x:=xo+(lx1+2*lx2+2*lx3+lx4)/(6); y:=yo+(ly1+2*ly2+2*ly3+ly4)/(6); vx:=vxo+(kx1+2*kx2+2*kx3+kx4)/(6); vy:=vyo+(ky1+2*ky2+2*ky3+ky4)/(6); [x,y,vx,vy]; end proc: Error, invalid local declaration Please someone help me!!!!!!!!

## parameters assigned in the equation...

in maple after fitting an equation (A + B.x) in the experimental data, how to assign to parameters A and B the adjusted values will be assigned in the equation?

Thanks

## How to draw line following the gradient curve...

I have a surface described by the equation.

f := (x, y) -> 3*(1 - x)^2*exp(-x^2 - (y + 1)^2) - (2*x - 10*x^3 - 10*y^5)*exp(-x^2 - y^2) - 1/3*exp(-(x + 1)^2 - y^2)

with(plots):
plot3d(f(x,y),x=-3..3,y=-3..3,orientation=[-40,60,0])

If a drop of water were put at point f(0.2,1.4), how would we draw a line to follow it's path?  (is that the gradient curve?)

## Unexpected difference between products and sums wr...

I expect the output for the following code to be a Matrix containing 720 and a Matrix containing 21. What I get is a Matrix containing x^6 and one containing 21, which shows an unexpected difference between the parameter evaluation rule for Matrix products and that for Matrix sums. Is there a good reason for this, or is it a bug? Do any other binary operators between rtables also show this weirdness?

```proc(n::nonnegint)
local x, q, v:= <<x>>, s:= <<0>>, p:= <<1>>;
for x to n do p:= p.v; s:= s+v od;
p, s
end proc(6);```

## Need help with rtable_eval...

Why does the following code return a vector containing x rather than containing 1 and how can I correct it?

proc() local x, v:= <x>; x:= 1; rtable_eval(v) end proc();

My actual goal is to have a Matrix with a parameter inside a procedure and to create different instantiations of the Matrix in a loop by changing the parameter.

## What is the possible reason that cause error in ds...

What is the problem with the initialconsiditions that caused this error?

"Error, (in dsolve/numeric/DAE/initial) missing initial conditions for the following: {Integer}"

Thanks.

## Analytical integration bug...

Hi

I use Maple 2016.

The following command calculates semicircle perimeter, but it returns infinity.

`assuming`([int(sqrt(1+(diff(sqrt(R^2-(x-R)^2), x))^2), x = 0 .. 2*R)], [R > 0])

## running a file even after error...

I am running a for loop which for some loop index may give error message but it is fine for me to go with next loop indexes. but maple stop after the error message. How can I make maple to run even after the error message. Thank you

## How to put a symbol (like greek) before a variable...

Can I do something like it?

## fsolve does not return a solution...

Hi,

I am trying to solve 1 equation with goniometric functions so I know the range (0..2*Pi), but it just doesnt solve it (though it solved similar ones before).

Is there some way to get the solution?

## Problem in Solving a first-order linear differenti...

Hello,

I have a problem in solving a differential equation in maple. I got an error which is "unexpected occurence of the variables..." .  I have uploaded my full problem as a pdf and maple worksheet (mw) files.

Untitled_(4).pdf

Prob.mw

## Derivative of BesselJ(alpha, sqrt(u^2+v^2-2*uv*cos...

Hi,

What is the derivative of the composed Bessel function BesselJ(alpha, sqrt(u^2+v^2-2*uv*cos(phi))) with respect to u?

BesselJ(alpha, sqrt(u^2+v^2-2*uv*cos(phi))) is a composed function of the form f(g(u)) with f=BesselJ(u) and g=sqrt(u^2+v^2-2*uv*cos(phi)).

Best regards

## Odd problem with Physics[Vectors]...

I can't figure out the source of the problem.  Any ideas?

 > restart;
 > with(Physics[Vectors]):
 > Physics:-Version();

 > 3.0*_i + 4.0*_j;

 > 3.0*_i + 0.0*_j;

Error, (in Physics:-Vectors:-+) wrong sum of a vector with the scalar 0.

How do we handle this when it happens within a computation burried inside a proc?