## inflexion point with maple...

hello, i have some problems with maple. i need to know an inflexionpoint of the following function: f:= x->((x^3-x+1+(6/30))/(x^2-1)); i derivate till f'''(x) with the following commands dv1: D(f)(x); dv2: (D@@2)(f)(x); dv3: (D@@3)(f)(x); and here starts my problems. maple seems to do nothing. for dervation f'(x) and f''(x) it shows me nothing for derivation f'''(x) just a 0. i suppose the mistake is in front of the computer :O. so what is wrong? here my exact commands: restart; f:= x->((x^3-x+1+(6/30))/(x^2-1)); df1:= D(f)(x): df2:= (D@@2)(f)(x): df3:= (D@@3)(f)(x):

## do loops...

Hi I have constructed a do loop to represent an epidemic described by 3 equations. I have plotted these using the initial conditions given. If i want to identify the values of S[k], I[k] and R[k] at k=60 how do i enter this? And how do i find out the exact point where the epidemic reaches its peak?

## Physic problem...

I had the worst physic's teacher in High School so we did not learn a single thing. If you guys could help me I'd appreciate! I need to find the angle if A throws a rock at C. He throws his rock at 20m/s. C is on a 8metres building. A is 10metres away from C. With which angle (theta) A needs to throw his rock to hit C. Situation: http://img522.imageshack.us/my.php?image=problemkk3.jpg Equation: http://img519.imageshack.us/my.php?image=physicequationpa1.jpg

## Solving nonlinear ODE (nonlinear spring)...

Hi, I'am trying to solve a nonlinear (spring) ODE like: > ode := A*(diff(x(t), t, t)) + B*(diff(x(t), t)) + R(x(t)) = 1; ...So, I defined a nonlinear (elastic-plastic) resistance function R(x(t)): > xLast := 0; RLast := 0; Rmax := 1; > R := proc (x) > local RR, dx; > global xLast, RLast, Rmax, K; > dx := x-xLast; > RR := RLast+K*dx; > if Rmax <> elif RR <> end if; > xLast := x; RLast := RR; > return RR; > end proc; ...Set up the ODE: > xLast := 0; RLast := 0; > ode := A*(diff(x(t), t, t))+B*(diff(x(t), t))+R(x(t)) = 1;

## Functions of different scales in the same plot...

Is it possible to dislay two functions in different scales in the same diagram? E.g. one function taking values in the range 1..10 and another taking values in the range 0.01..0.1. The reason I want to do this, is to display functions (on different scales) which interact in the same diagram so they can be easily compared. I can, of course blow one function up, but I find that slightly dissatisfying, as the numbers loose their meaning, and understanding the plot becomes more difficult. If this is not possible, is there a way I can effectively export the ploted 'data' and redraw the graphs in another more suitable program? Any tips or help appreciated.

## I'm looking for a MapletBuilder-Guide!!!...

Hi! I'm searching for a useful guide of the MapletBuilder (for Maple 11). I know how to create Boxes 'n' Stuff. Now I want to assign commands to the buttons,which should be executed by pushing them but I don't know how to do that. By that I mean where to put them and what kind of commands exist or do I have to use. I need a guide with some examples. It would be great if anyone could help me. Thanks paience

## Summations involving 0^n...

Dear All, I seem to be having trouble with 0^n in maple, can someone help? Essentially, I have a complex function that simplifies under certain conditions to
f:=1.*0.^n/factorial(n);
but
sum(f,n=0...0);
gives 0. Whereas,
evalf(subs(n=0,f));
gives 1. Any ideas? Thanks Colin

## Maple And The Convergence Of Infinite Series...

Can Maple be used to test infinite series for convergence ? Are the many tests for convergence already built-in Maple ? Thanks, v/r,

## Infinite Sum Question...

Please Help, Show that Sum(1/((2*n-1)*(2*n+1)), n = 1..infinity) = 1/2) Hint. (Show by mathematical induction that s[m] = m/(2*m+1) Thanks, v/r,

## Procedures...

Does anyone know how to write a procedure for simpsons rule using the trapezium rule. I wrote a procedure for the trapezium rule but it wont let me put it in the simpsons rule. Maple keeps saying that local is wrong. Please help!

## piod controller...

i WANT TO DEVELOP A MICROCONTROLLER BASED PID TEMPERATURE CONTROLLER.THE USER WILL SET THE DESIRED TEMPERATURE THROUGH KEYBOARD.I WILL BE USING A TEMPERATURE SENSOR(IC LM35DZ) WHICH WILL BE INPUT TO MICROCONTROLLER 8051 WHICH WILL IMPLEMENT PID ALGORITHM TO CONTROL A RELAY AND HENCE EITHER TURN ON A HEATER OR A COOLER.AN LCD WILL ALSO BE INTERFACED TO DIPLAY THE SET TEMPERATURE AND ACTUAL TEMPERATURE. I DO NOT KNOW THE C CODE FOR THIS.IF ANYONE HAS WORKED ON SUCH KIND OF SYSTEM ,THEN PLEASE SEND ME THE CODE.I WILL BE REALLY VERY GREATFUL

## Does maple has sleep function?...

When I execute a proc of Maple, Can I make the process sleep for several seconds? Just like other programming languages sleep function. Thanks.

## Find tangent...

I have an equation lets say f(x). I derivate it then I need to find the equation of the tangent that touches f(x) at two different places.