4 replies to this topic

[enakta13]

For instance, consider a
function y = f(x).

_____________
x | y
------------------
1 | -3
3 | 0
4 | 30
6 | 132
------------------

Now I need to find the value of y for x=5

Can I solve this using my fx-991 ES, if yes please tell me how

Thanks in advance

[verena]

Well you say you have a function: y = f(x).

But then you present a table:
_____________
x | y
------------------
1 | -3
3 | 0
4 | 30
6 | 132
------------------
This is not a function.

To find the value for x=5 you have to either determine the function first and then just calculate it for x=5, the problem being, there are many possible functions that will yield that table;
or linearly interpolate between 4 and 6, x=5 resulting in y=81, via:
Let x1 be the x-value smaller than your x (here,4); x2 the x-value larger than your x (here,6); y1 and y2 the corresponding y-values (here, 30 and 132); then

y = y1+(x-x1)/(x2-x1)*(y2-y1) = 30+(5-4)/(6-4)*(132-30) = 30+1/2*102= 30+51 = 81.

[TovAre]

For instance, consider a
function y = f(x).

_____________
x | y
------------------
1 | -3
3 | 0
4 | 30
6 | 132
------------------

Now I need to find the value of y for x=5

Can I solve this using my fx-991 ES, if yes please tell me how

Thanks in advance

I think perhaps it only supports quadratic regression, a cubic regression seemed like pretty fair approximation (in fact the formula looks a bit text-book-like).

f(5) = -0.5x^3 + 13.5x^2 - 46x + 30 = 75


With quadratic regression I get f(5) = 72 (with messier numbers in the formula).

[wrya Abdullah]

Yes you can do it just follow this instruction:Its simple
press mode
3;stat
2;A+Bx
l x l y l
l 2 l 4.6 l
l 4 l 5.9 l
press; AC
press;5.9
press; shift
press;1
press;7 (reg)
press;5 (comma)
press;=
u will get ans

source:
http://www.fixya.com...polate_in_casio

[ZweiLynx]

@ Verena

He didn't say he has a function y = f(x) ; he said to "consider" a function... That means the table presented contains the data that describes the unknown function f(x) to derive.