TI 86 help
 

I suppose this is a very simple thing to do, yet for the life of me I cannot figure it out. I've searched about 20 different websites, read the manual and still cannot figure it out.

I need to know how to graph equations like 3^x=21 while solving for x. I need the x-intercept from the graph on the caculator.

So far this is what I have:

'graph'
y(x)
\y1=[equation here]

However I don't think that is correct.

Anyone?

I hope you're not trying to find the x-intercpt of y=3^x.

I'm working with a TI85, so it might be a tad different, but that should work. y1=3^x will get you a graph.

I'm having trouble seeing how to get the x intercept (assuming it were an equaion with an x intercept). Y intercept is easy. I'll see what I can figure out.

Okay, this seemed to work, don't ask me why.

Once you have your graph, select "Math" from the function menus (should be the f1 key after you hit "more"). Then select "Root" (should be f3). Move the cursor to just left of the x-intercept and press enter. It should display the x-intercept (point where y=0) at the bottom of the screen.

I'll ask Tori. Brb.;)

D'OH! I forgot to post an update. I figured out how to do this problem..

But now I have an even more complicated problem to do

5^(-x+3)=91. When I enter it I get an error. Sigh. I hate math.

Thank you everyone in advance for your help!

I can help with 1+1=2

Tori wants to know why you are cheating....lol.

(I told her I thought this was for school).

Eww, math.

Tell Tori that in college you are allowed to use fancy smancy caculators to help you with your math. In fact these problems say "with a graphing caculator find....". :D

Lol- no way! She'll expect to be able to do so, too!

I think in most advanced math (late high school and college) classes a graphing caculator is mandatory.

Tell her I'm not cheating, the teacher allows this and the instructions say to use a caculator.

Oh, I'm teasing- I told her that last night. She thought it was pretty cool you get to use a calculator, though.

:) whew. I'm a bit fried at the moment... stupid math.

Another LoTter and I were going to run for governator on the 'make math illegal' platform.

I would so vote for you.... even from up here in the PNW! (We're good at throwing elections;) ).

Yeah, but that will soooooooo kill every almost every job in silicon valley, and say goodbye to all the computer games..................mmmmmmmmmmmmmmm, computer games.....:homer drool:



But on the programmers of California's behalf, I will have to vote for the other guy in that election.....sorry....:p

Really? In the pre-calculus and calculus classes I took at Santa Monica College five years ago, we were expressly forbidden to use graphing calculators. The administration's stance was that they wanted to make sure we knew how to do it the old-fashioned way. I would've given anything to use a graphing calculator on some of those stupid toroid shape problems on my exams.

Ya, we can use graphing caculators (certain ones like the TI 86, but they don't allow some). If I had to do this the old fashioned way I'd never pass. And at this stage in the game I'll do *almost anything to pass this stupid class. Operative word being *almost.
meaning no cheating, nothing unethical etc...