# Thread: How would I enter the following in my TI-89...

1. ## How would I enter the following in my TI-89...

How do you enter cube roots and radicals into the TI-89? I can't really give an example using the computer keyboard, so an example is on the following page:

Example

Thanks,
Noah

2. $\sqrt[3]{6x+9}+8$ would be
Code:
(6x+9)^(1/3)+8
In other words, if you want to take the nth root of say, abc, it would be
Code:
(abc)^(1/n)
Remember to put 1/n in parenthesis.

3. Hey thanks a lot for your help. Could you tell me how to enter the three problems on the page below on my TI-89

Example

Thanks,
Noah

4. Here's one example. The others are entered the same.

5. Thanks for your response.

How do you enter the 2nd and 3rd ones:Example
I was looking for how to enter the problems instead of the answers.

Thanks,
Noah

6. Originally Posted by cachemony
...
I was looking for how to enter the problems instead of the answers.

Thanks,
Noah
Hello,

I'm not quite certain what you mean here.

From the screenshot you can see how to enter a term into the TI89. There are only a few rules you have to use strictly:
1. All parts which belongs together must be put into brackets: Denominators, numerators, radicands, ...
2. Superflues brackets are suppressed by the TI89 automatically. So it is better to use an additional pair of brackets.
3. A leading negative sign is connected to the key $\boxed{(-)}$. If you use the normal operation sign for subtraction you'll get an error message.

4. I've attached 2 screenshots. Compare the input line and the result on the screen.

7. Thanks a lot for all the help from everyone.

I need help with a few more....how would I enter the following into my TI-89: How do you enter logarithmic functions?

1. 4loga-(-x-4) - 3loga(x+4)

2. logx100 + loga0.1

3. When I try to graph the following it says I have Undefined varibales. What does that mean? how do I graph the following:

(x+7)² - (y+2)² = 36

Thank You.
Noah

8. Originally Posted by cachemony
Thanks a lot for all the help from everyone.

I need help with a few more....how would I enter the following into my TI-89: How do you enter logarithmic functions?

1. 4loga-(-x-4) - 3loga(x+4)

2. logx100 + loga0.1

3. When I try to graph the following it says I have Undefined varibales. What does that mean? how do I graph the following:

(x+7)² - (y+2)² = 36

Thank You.
Noah
Hello Noah,

the TI89 has one build-in logarithmic function: The ln-function which you find with $\boxed{2ND}$ + $\boxed{x}$. If you want to calculate logarithms to another base you have to use the base-change-formula:
$\log_b(x) = \frac{\ln(x)}{\ln(x)}$

to #1.: I assume that you mean:
$4 \cdot \log_a((-(x-4) - 3 \cdot \log_a(x+4)$. If so then type:

4*( $\boxed{2ND}$+ $\boxed{x}$-(x-4)) / $\boxed{2ND}$ + $\boxed{x}$a)-3*( $\boxed{2ND}$ + $\boxed{x}$x+4) / $\boxed{2ND}$ + $\boxed{x}$a)
$\rightarrow ~~~~~~~~~~~~~~~~~\uparrow ~~\uparrow \text{attention: these are different negative signs for your TI()}$

But unfortunately your TI89 will not simplify or transform this term.

to #2.: Are you sure that there isn't a typo?

to #3.: Your TI89 is set to function mode (I assume). The calculator is not able to handle relations in multiple variables. To graph this hyperbola you first calculate equations of functions by solving the original relation for y. You'll get 4 different equations. (see attachment HYP2FUNC1)
Copy the results into the input line and store the different functions into the y= editor by using the $\boxed{STO\blacktriangleright}$ key.

In the WINDOW editor Use the settings
xmin = -16
xmax = 8
xscl = 1
ymin = -8
ymax=8
yscl=1
xres=1
Here it is necessary to set xres=1 because otherwise the gap between the different graphs will be to large.

9. You can use 'log', but you have to type it in. There is no 'log' key.

10. Originally Posted by galactus
You can use 'log', but you have to type it in. There is no 'log' key.
Hello,

thanks!

But obviously the log-function of the TI89 means $\log_{10}(x)$ which I know as $\lg(x)$

11. How do I get my TI-89 to divide this: (6x3 - x2 - 5x + 4) ÷ (3x - 2)

When its entered, it just displays it as a fraction.

How do I get it to perform the division?

Thanks,
Noah

12. Originally Posted by cachemony
How do I get my TI-89 to divide this: (6x3 - x2 - 5x + 4) ÷ (3x - 2)

When its entered, it just displays it as a fraction.

How do I get it to perform the division?

Thanks,
Noah
Hello,

if the build-in program can't simplify the quotient it is only repeated.

To do the synthetic division you have to use the command

propFrac((6x^3-x^2-5x+4)/(3x-2))

You get the result: $\frac{2}{3x-2} +2x^2 + x - 1$

You find the command propFrac( at the menu F2 Algebra #7

By the way: Please do yourself and do us a favour and start a new thread if you have a new problem. Otherwise you risk that nobody at the forum notices that you need help.

13. ## square roots

how do I input the proper info on these problems:

the square rootof 32 - the sqaure root if 50xx

how do i input the info for graphing on:

2x + 3y+=6
-8x - 12y =-24

14. ## square roots

how do I input the proper info on these problems:

the square rootof 32 - the sqaure root if 50xx

how do i input the info for graphing on:

2x + 3y+=6
-8x - 12y =-24

15. ## square roots

how do I input the proper info on these problems on the ti-89 calculator

the square rootof 32 - the sqaure root if 50xx

how do i input the info for graphing on:

2x + 3y+=6
-8x - 12y =-24

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