Knowledge Base

Solution 39778: Intersection command for conic relation displays an inaccurate result on TI-Nspire CX Family.

Why does the intersection command for a conic relation display an inaccurate result on TI-Nspire CX Family?

Depending on the intersection command used the answer displayed may be inaccurate.

For example:

1) Open a graphs page and then press [Menu] [3: Graph Entry/Edit] [2: Relation].

Enter the function:

x+y-3=0

2) Press [Tab] and enter the function:

x^2+y^2+13*x+3*y-16=0

3) After the functions have graphed press [Menu] [8: Geometry] [1: Points and Lines] [3: Intersection Points] then select relation plot 1 then relation plot 2.

The intersection points found will be listed as (-1.12,4.12) and (-0.881,3.88) .

To find a more accurate intersection avoid using the Geometry intersection command and instead use [Menu] [6: Analyze Graph] [4 Intersection] command which will produce a more accurate result of (-1,4)