Question about Texas Instruments TI-89 Calculator

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Expand? When I hit Expand (x-5)^3 I get (x-5)3 which is not what I am looking for. I have spent hours looking for the solution and haven't gotten anywhere.

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What you're typing in and thus asking for is the cube of the expansion of (x-5), and that is exactly what the calculator is giving you. The expansion of (x-5) is (x-5), of course, and the cube of that is (x-5)^3.

What you want is the expansion of (x-5)^3. To get this you need one more set of parentheses.

expand((x-5)^3)

Note the two open parens immediately after the "d".

Posted on Jan 17, 2010

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My Casio classpad won't give me the correct answer


I am not sure about what you want. The expression is in its most compact form. So I am assuming you want to exapnd it. The command for that is exapnd( . Just type it using the keyboard or look for it under the Action>Transformation menu.
expand((x+5)^6) [EXE]

Here is a screen capture of what you should get. Notice that I cleared all 1-letter variables to erase any value stored in x.

7_11_2012_2_45_49_pm.png

Jul 11, 2012 | Calculators

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Whenever the command expand, diff or integrate are use it comes up with wrong argument. I have tried to clear all variables and default the set up but to no avail.


I believe you are using the wrong syntax for the commands.
diff ( function, variable) Example: diff (sin(x^2), x) sgould give you 2.x.cos(x^2)
expand( will expand an expression that has parentheses: expand( (a+b)^2) will give a^2+2a.b+b^2
Integrate $
$ ( tan^-1(x), x) willl give x.tan^-1(x) -(1/2) ln ('x^2+1')

Check the syntax of a command before using it. You will find the list of all comands and their syntax in the reference manual.

Aug 22, 2011 | Casio ClassPad 300 Calculator

1 Answer

Calculator is not expanding or factorising algebraic expressions as should. Gives answers in curly brackets which seem unrelated.


I am somewhat puzzled at your affirmation concerning factoring and expanding algebraic expressions. The TINspire does not do symbolic algebra, only the TI Nspire CAS does.
If you have the TINspire CAS, (version 2.x) you can
  1. press the HOME button, then select A:Calculate.
  2. In one of the pages, press MENU.
  3. Select [3:Algebra]
  4. Use Down Arrow or enter the number 2:Factor, or 3:expand
  5. In the command line, expand( , complete the command by entering the expression, close the right parenthesis and press [ENTER].
  6. The calculator should give you the expanded result.

Feb 08, 2011 | Texas Instruments TI-Nspire Graphic...

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I can't do simple commands like expand( ), integrade, differentiate,... I know that the command is expand(X^3-1) but the answer i get is always { } with no answer in it thanks for ur help Tom


Hi tomschepers1,

I can see why the expand command doesn't work with the equation your inputting. Even though, expand(x^3-1,x) would work better. The expand command does not expand to a complex form. But, your other functions should have worked. The {} tells me your asking the calculator to do something it can't do or, is to big to do, (to many arguments).

So, you need to use the NewProb command at the Home screen. On the command line at the Home screen press, [CLEAR]. Then press, [2nd][F1][2][ENTER] and, the NewProb command will be entered at the Home screen. If that doesn't enable the functions to work properly, then you need to reset your RAM to default conditions. To reset the RAM to it's defaults press, [2nd][MEM][F1][Right Arrow][2][ENTER].

If you have any question about my solution, please post your comment and, I'll respond quickly.

Jan 14, 2011 | Texas Instruments Voyage 200 Calculator

1 Answer

How can you expand (x-0.3)(x/2+.15) on TI-89 tintanium


In Home screen press [F2: Algebra] then select [3:expand(]. The command echoes on main command line. Complete the argument by typing in (x-0.3)(x/2 plus 0.15) and close the right parenthesis of the expand( )function.

You can also use the identity (special product) (a-b)(a plus b)=a^2-b^2. It is not that clear here, but if you you factored out the 1/2 you will see it.
1/2*(x-0.3)(x plus 2*0.15)=1/2*(x-0.3)(x plus 0.3)= 1/2*(x^2-0.3^2)

Nov 14, 2010 | Texas Instruments TI-89 Calculator

1 Answer

A carpenter was contracted to repair a kitchen for $18000, the work took him 6 hours more than he has estimated and as a consequence, he earned $100 per hour less than he had estimated. how many hours had...


I will try to solve it systematically so it will be easier to understand. Note: The solution involves solving a quadratic equation.

Let amount of hours estimated be x:

Expected rate: $18000/(x hours)

Time spent extra: 6 hours.

Totals hours spent: (x + 6) hours

New rate: $18000/(x+6 hours)

Now:

18000/(x+6) x

The new rate is less than old rate by $100, therefore we can make the above inequality equality by adding $100 to the new rate.

18000/(x+6) + 100 = 18000/x

Solve by cross multiplaction:

(18000 + 100(x+6) * x = 18000 * (x+6)

18000x + 100x(x+6) = 18000x + 108000

Simplify:

100x(x+6) = 108000 (cancel 18000x on both sides)

x(x+6) = 1080 (divide by 100)

x^2 + 6x - 1080 = 0

Solve the above quadratic equation by any method (completing square, factorization or quadratic formula)

x = (-b+-(b^2 - 4ac)^.5)/2a where a = 1; b = 6; c = -1080

x = 30 or -36 (hours cannot be negative so disregard this result)

Therefore x = Estimated time = 30 hours

Check:

18000/30 = $600 per hour x+6 = 36 $18000/36 = $500 or $100 per hour less than estimated

Nov 12, 2010 | Calculators

1 Answer

Incorrect answer when expanding on casio classpad 330


Hello,
I don't quite understand what you mean by expand a problem. The expand( command is used to develop expressions such as (ax+b)^2.
For this expression the calculator will give a^2.x^2+2.a.b.x+b^2, which is the correct answer. The dots stand for the multiplication sign.
If you tell us what you are trying to do, we might be able to advise you better.
Hope it helps.

Feb 26, 2009 | Casio ClassPad 300 Calculator

1 Answer

Algebra


for expand, you don't need to put ",x" at the end.

just do: expand( (x-5)^3 )
and you should get: x^3-15x^2+75x-125

May 09, 2008 | Texas Instruments TI-89 Calculator

1 Answer

TI-89 Factoring Not Working


I think what you want to do is not to factor but to expand, which is the option right under factor [F2, 3]. expand((x-5)^2) = x^2-10x+25

Jul 13, 2007 | Texas Instruments TI-89 Calculator

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