10 replies to this topic

[betoe]

Hi guys in this topic i will post any math doubt that i have with my classpad.
Today i had this one, hope that someone can understand & help me:

I have this math expression:
1 + a + a^2 + a^3 + .... (it spreads to infinite, n)

I want to re-write this via classpad (i want to apply this for exams), my teacher give us this result:
1 - a^(n+1)
1 - a

Does some classpad command do that?

[Lovecasio]

Yes, I found that.
Procedure:
Press KeyBoard, 2D, then find the symbol for sum (upcase sigma)
In the lower box, tap x. Next, tap 1 to the right box.
Next, In the top box, input n.
In the last box, input a^x
After that, tap everywhere out of Sigma symbol and tap + 1.
Press EXE.
To get the same result with your teacher, select Action, Transformation, Combine, and tap ans, EXE. You will get the same result.
GoodLuck
Oh, what grade are you in?

[betoe]

Wow thank you so much Lovecasio!

Right now I'm studing the 7th of 8 semester of electronic engineer.

[Lovecasio]

Quicker way:
As I say above, In the lower box of Sigma symbol, you change x=1 to x=0.
Then, you dont need to +1 because a^0=1 with all a<>0. Then press EXE and you will go directly to the result.

If you have other problems, put it here so we can learn more about the ClassPad.

[betoe]

Well thanks a lot. Tomorrow (November 4) i will study for a signal digital processing (a lot of maths), surely i will have new doubts but probably it will be too late for scream here for some help . But i will post it anyway.

[betoe]

Hi guys Abel make this post, he has this doubt:

"The ModBox for represent statics variables (one dimension) dont work; its a method for determinate "outliers", but it really do the same graphic that the "box and whiskers" option."

I hope somebody can help him (i dont know and i dont like anything about statics ).

[betoe]

Hi all you guys, i want to make graphics for integers numbers of x (discrete time), and i try this:

y=sin(x)|x=int(x)

This work well in the classpad manager, but in the classpad no
Try this and let me know what happend...

[Lovecasio]

Hi.
I tried the code you write, both ClassPad and the manager produced the same result: the graph window appear some dot. What did the graph window appear on your ClassPad?

Oh, could someone help me to solve: (sin(3x/2))^2=sin(x)sin(3x).

[betoe]

damn i had a error when i wrote the code on my calc.
Strange, other guy had the same error that me.

[BiTwhise]

Oh, could someone help me to solve: (sin(3x/2))^2=sin(x)sin(3x).

Well,

'x=0+2k*pi' is one obvious solution

-- EDIT --
Solutions:

x = 2k*pi
x = 2/3 * pi + 2k*pi
x = pi/6 - 4/3 * pi + 2k*pi
x = -pi/6 + 4/3 * pi + 2k*pi

[Lovecasio]

Oh, thanks alot.