Evaluate the function at the given numbers (correct to six decimal places).
f(x) = (x^2 - 6x)/ (x^2 -x -2)
x= -0.9 y: -21.41
Webassign marked this as incorrect. How is this incorrect? I plug that exact value into the the equation on my ti 83 and got that answer. Webassign also marked me wrong for other decimal values except for
0, -.5, and 2
Okay I changed it in the setting to "float" but some numbers are not reaching the 6 decimal place.
For value x value -0.9 i got -21.41379.
I plug that entire number into the webassign and it still marked me incorrect.
I also tried adding 0 at the end to meet the "6 decimal place" but that failed.
Here's a thought, old fashioned as it is: Type in ((-0.9)^2 - 6(-0.9))/ ((-0.9)^2 -(-0.9) -2).
It's also worth remembering GIGO.
Not too many years ago I'd expect a student to be capable of replacing -0.9 with -9/10 and then calculating an exact value using fractions, without using a calculator. Times change.
I admit that I rely heavily on my calculator but during testing situations, I need the calculator's accuracy and speed so setting it up to display what I what and when I want is crucial.
Also i understand you can easily plug in the original equation but I was just listing -0.9 as 1 x value out of 14 x value that I had to calculate for. I ended up doing this for the homework anyways because I can not set up my ti83 to show more than 5 decimal places in the graph/table
plugging in every single x value ranging from -0.5 through -1.001 into the original equation might not be the most effective way to work during a 1-2 hour testing period.
I can find the exact value of y for these values of x (and x = 0 is particularly simple, by the way) faster using mental arithmetic than finding, turning on and using a calculator. And it is very simple to work using pen and paper .....
I'd argue that a student with a competent grasp of basic arithmetic should be able to as well, at least for x = 2 .....
It's well and good to use a calculator, but like any tool, the calculator is only as effective as the mind that is directing it.