TI-89 question (graphing x and y)

SyN65

Basically I have to graph x and y but the 89 isn't letting me.

x = -y^2

y = x + 20

I'm sure I have to be in a specific mode or something - I tried function and parametric but neither worked and give me the error "Undefined Variable".

Any help would be much appreciated.

MATLABdude

Welcome to PhysicsForums!

The key point here is that you're graphing FUNCTIONS of x. Your second equation should work all right (just type x+20 for y1 or y2). For more on basic graphing, click on the "Basic Function Graphing" chapter in the TI-89 manual:
http://education.ti.com/guidebooks/g...k_Part2_EN.pdf

As for your second equation, you just need to solve for x as a function of y (remember, you need both the positive and negative branches of the square root).

Good luck!

trautlein

You want to be in function mode. Listen to the above poster and reply if you still need help : )