Drawing Circles with TI-89! HELP!!!

Test Preparation
1

<p>does anyone know how to draw a circle with TI-89??</p>

<p>not like y=(r^2-x^2)^1/2 thingies...</p>

<p>can we put x^2+y^2=4 on homescreen and get the graph of it???/</p>

<p>HELP PLEASE!!</p>

2

<p>You'd need a separate conics program because circles aren't functions.</p>

3

<p>ever hear of the vertical line test?</p>

4

<p>easier TI89 question...how do i use the ncr and npr functions?</p>

<p>for example i have 5 books and i want to use any combination of 2...on the ti83 i do 5 Ncr 2, but it gives me an error on the 89.</p>

5

<p>nCr(5,2)</p>

<p>--
The message you have entered is too short. Please length your message to at least 10 characters.</p>

6

<p>umm..theres another way todo it (thought i dont see whats so helpful about graphing circles), u go to the home screen ... Solve the eqution for y ..by typing solve(x^2+y^2=4,y) then u should get TWO answers ..just copy them (hold shift until u highlight all of it, then press DIAMOND + Shift) then paste them into the y equal editor (diamiond+esc) then graph BOTH of them..it wont be THAT acuartte but it ll still be a circle</p>

7

<p>Convert the equation to a polar function.</p>

8

<p>yes, polar. go to mode screen, then change function to polar. convert the equation to a polar equation. then go to the y screen where you normally put in equations and then enter in 2 for r and it should be a circle.</p>