Amitabh Biswas

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11 years, 339 days

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These are replies submitted by Amitabh Biswas

Thanks very much.

Thanks very much.

Thanks a lot.

Thanks a lot.

I know it's a silly question for a used-to user like me,but I just don't have the time for the search,I need it ASAP.

I know it's a silly question for a used-to user like me,but I just don't have the time for the search,I need it ASAP.

I want a function say m(h),& want to plot m vs h.

I don't want the plot of the actual plot,only its inverse.

NB:Please see the attached WS file,the written code has syntax errors.

Thank you.

I thought I said that the attachment is here because the procedure I wrote may contain some syntax errors.

In the attached ws I used 'return'.Now, talking about modern & old styles,I started to learn Maple using some books which involves solving physical problems using Maple.I was suggested to learn Maple using the examples of those books beside taking help from Maple,and most of them were "old" (most of them used Maple V-9 as standard),I saw a lot of uses of 'RETURN' there.I learned return later though,I used it in the ws.If I stared my learning using some Maple user manuals or programming guides I think I didn't grow the habit of using "old" stuffs.Now I'm not trying to sound rude,but you know  what,10 or 100 years old, RETURN works!

Why it is not a good idea to unprotect D(though it was not necessary here,I wrongfully thought that since I was using D,I should unprotect it)If I don't use differentials/differentiation using D after unprotect it?

Could you pls explain why loading the package outside the procedure is also a bad idea?I thought(May be once again wrongfully)once I load a package at the beginning,I don't have to worry about using all kinds of stuffs involving that package until I restart.Also I had to write some matrices after the procedure(see the ws).I thought I covered the procedure+after-procedure matrices by loading the LinearAlgebra package at first.

See the help page by typing

?solve;

See the help page by typing

?solve;

@ummu 

Yes,you can code in maple,it's called Maple programming.See following help pages

?introductory programming guide;

?advanced programming guide;

If you have any experience with C/C++,or Pascal,or Basic,it will help,If you don't,still no problem since it is interactive.

 

By the way, why you didn't use the eqn : v^2=u^2-2*a*s  directly to solve your problem?It is another equation of motion for

constant deceleration.You have v=0(part a & b),u=88(part a),s=100(part a),you can get a or k in your case,just by simply solve for a

or k,you actually didn't need those other 2 equations as long as you directly use the above eqn (actually the above eqn can be

derived from those other 2).

I assume it was mandatory for you to solve this problem using differential equations. 

@ummu 

Yes,you can code in maple,it's called Maple programming.See following help pages

?introductory programming guide;

?advanced programming guide;

If you have any experience with C/C++,or Pascal,or Basic,it will help,If you don't,still no problem since it is interactive.

 

By the way, why you didn't use the eqn : v^2=u^2-2*a*s  directly to solve your problem?It is another equation of motion for

constant deceleration.You have v=0(part a & b),u=88(part a),s=100(part a),you can get a or k in your case,just by simply solve for a

or k,you actually didn't need those other 2 equations as long as you directly use the above eqn (actually the above eqn can be

derived from those other 2).

I assume it was mandatory for you to solve this problem using differential equations. 

@ummu 

Well,sys and ic are not commands.

What you are doing here is just solving a second order differential equation,namely:

diff(s(t),t$2)=k.                    ...............................(1)

Now I split this 2nd order de into 2 1st order des,I denote the velocity by v , its entirely up to me;such as:

diff(s(t),t)=v(t).......................................................(2-A)

Now you can see that the eqn(1) is just

diff(v(t),t)=k.........................................................(2-B)

(2-A) & (2-B) are equivalent to (1).Now you can see (2-A) and (2-B) are not 2 independent equations,they depend on each other and

together they are actually eqn(1),so they are a system of 2 simultaneous eqns.Now what I have to do is to solve (2-A) & (2-B) together,i.e. I have to solve the system.Here I declare the system by 'sys' and assign it to the 2 equns,you can give your system any name you wish.It is not a command,It just a name I assign to the equations.

You know that to find the solution(if solution exist) of a de without any integrating constant,we need to know the initial condition/conditions.The number of condition/s depends on the order of the de.If the de is 1st order we need only 1 initial condition,if it is of order 2 we need 2 conditions and so on.Here we need 2 conditions:

s(t)=0 at t=0,i.e. s(0)=0 obviously because at start the car travels no distance.

& v(t)=88 at t=0,i.e. v(0)=88 ft/sec.sec because when it starts it has already a speed of 88 ft/sec.sec,it doesn't start from rest.

I denote these 2 initial condition by 'ic'.So ic is not a command,I named the conditions ic.

@ummu 

Well,sys and ic are not commands.

What you are doing here is just solving a second order differential equation,namely:

diff(s(t),t$2)=k.                    ...............................(1)

Now I split this 2nd order de into 2 1st order des,I denote the velocity by v , its entirely up to me;such as:

diff(s(t),t)=v(t).......................................................(2-A)

Now you can see that the eqn(1) is just

diff(v(t),t)=k.........................................................(2-B)

(2-A) & (2-B) are equivalent to (1).Now you can see (2-A) and (2-B) are not 2 independent equations,they depend on each other and

together they are actually eqn(1),so they are a system of 2 simultaneous eqns.Now what I have to do is to solve (2-A) & (2-B) together,i.e. I have to solve the system.Here I declare the system by 'sys' and assign it to the 2 equns,you can give your system any name you wish.It is not a command,It just a name I assign to the equations.

You know that to find the solution(if solution exist) of a de without any integrating constant,we need to know the initial condition/conditions.The number of condition/s depends on the order of the de.If the de is 1st order we need only 1 initial condition,if it is of order 2 we need 2 conditions and so on.Here we need 2 conditions:

s(t)=0 at t=0,i.e. s(0)=0 obviously because at start the car travels no distance.

& v(t)=88 at t=0,i.e. v(0)=88 ft/sec.sec because when it starts it has already a speed of 88 ft/sec.sec,it doesn't start from rest.

I denote these 2 initial condition by 'ic'.So ic is not a command,I named the conditions ic.

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