Modelling questions

[fleet street]

Hi, I was wondering how to solve questions of the type:

is an appropriate model for the following data. The value of a, to the nearest whole number, is
x|     1    |     2    |
y|286.42|776.85|

A. 100, B. 103, C. 105, D. 200, E. 280


is an appropriate model for the following data. The values of a and b, to the nearest whole number, is
x|   0  |   1    |     2  | 3
y|7.00| 7.69  | 8.09|8.39

A. a=-3, b=6
B. a=-2, b=6
C. a=-1, b=7
D. a=0, b=7
E. a=1, b=8

If it matters, I'm using a Classpad.

Thanks!

[Phy124]

Hi, I was wondering how to solve questions of the type:

is an appropriate model for the following data. The value of a, to the nearest whole number, is
x|     1    |     2    |
y|286.42|776.85|

A. 100, B. 103, C. 105, D. 200, E. 280


is an appropriate model for the following data. The values of a and b, to the nearest whole number, is
x|   0  |   1    |     2  | 3
y|7.00| 7.69  | 8.09|8.39

A. a=-3, b=6
B. a=-2, b=6
C. a=-1, b=7
D. a=0, b=7
E. a=1, b=8

If it matters, I'm using a Classpad.

Thanks!

You sub in the values for y and x into your equation and equate it for the unknown.

If you have one unknown you only need 1 coordinate, if you have two unknowns you need 2 coordinates etc.

So in the first example let's take the point (1,286.42):





On calc

In the second example we need two points let's take (0,7.00) and (1,7.69):






On calc:

edit: changed to in calculator syntax

[fleet street]

Thanks! Not that I'd expect you to have any solution to this, but I entered the second set of equations in the calculator, and it couldn't return a result even after leaving it for 3 minutes. Is it like this on yours too?

[polar]

Thanks! Not that I'd expect you to have any solution to this, but I entered the second set of equations in the calculator, and it couldn't return a result even after leaving it for 3 minutes. Is it like this on yours too?

don't use , I did that too and it took too long so, I used instead and it was a lot faster on my classpad

[Phy124]

Yeah, as polar said, if your calculator is taking more than a few seconds solving something like this it's probably worth stopping the calculation and trying different points if possible.

[fleet street]

don't use , I did that too and it took too long so, I used instead and it was a lot faster on my classpad

Wow, you're right, it actually worked.

Yeah, as polar said, if your calculator is taking more than a few seconds solving something like this it's probably worth stopping the calculation and trying different points if possible.

Thanks, I'll keep this in mind.

[Zealous]

Yeah, as polar said, if your calculator is taking more than a few seconds solving something like this it's probably worth stopping the calculation and trying different points if possible.

Any ideas how to stop an Nspire CX CAS if its taking a while (cancel a calculation?) I've actually crashed my CAS with some Further stuff because the cursor just showed a spinning clock thing for a few minutes.

[BubbleWrapMan]

Holding down [esc] should do it

[lzxnl]

On my old Ti-Nspire, removing the battery cover, without removing the batteries, and replacing the battery cover would turn the calculator off and when turning it back on, I did not have to wait for the usual starting animation. It was very helpful for cancelling calculations.