TI 86 help

BarTopDancer · 05-14-2005, 11:26 AM

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?

Ghoulish Delight · 05-14-2005, 11:40 AM

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.

Ghoulish Delight · 05-14-2005, 11:46 AM

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.

wendybeth · 05-14-2005, 10:42 PM

Quote:

Originally Posted by BarTopDancer

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'll ask Tori. Brb.

BarTopDancer · 05-14-2005, 10:50 PM

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!

Kevy Baby · 05-14-2005, 11:00 PM

I can help with 1+1=2

wendybeth · 05-14-2005, 11:12 PM

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

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

BarTopDancer · 05-15-2005, 09:47 AM

Quote:

Originally Posted by wendybeth

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

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

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....".

wendybeth · 05-15-2005, 10:06 AM

Quote:

Originally Posted by BarTopDancer

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....".

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

BarTopDancer · 05-15-2005, 10:17 AM

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.

05-14-2005, 11:26 AM	#1
BarTopDancer Prepping... Join Date: Jan 2005 Location: Here, there, everywhere Posts: 11,405	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? __________________ Spork is the new MacGyver Postcards From My Edge
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05-14-2005, 11:40 AM	#2
Ghoulish Delight I Floop the Pig Join Date: Jan 2005 Location: Alternative Swankstyle Posts: 19,348	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. __________________ 'He who receives an idea from me, receives instruction himself without lessening mine; as he who lights his taper at mine, receives light without darkening me.' -TJ
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05-14-2005, 11:46 AM	#3
Ghoulish Delight I Floop the Pig Join Date: Jan 2005 Location: Alternative Swankstyle Posts: 19,348	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. __________________ 'He who receives an idea from me, receives instruction himself without lessening mine; as he who lights his taper at mine, receives light without darkening me.' -TJ
	Submit to Quotes

05-14-2005, 10:50 PM	#5
BarTopDancer Prepping... Join Date: Jan 2005 Location: Here, there, everywhere Posts: 11,405	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! __________________ Spork is the new MacGyver Postcards From My Edge
	Submit to Quotes

05-14-2005, 11:00 PM	#6
Kevy Baby Chowder Head Join Date: Jan 2005 Location: Yes Posts: 18,500	I can help with 1+1=2 __________________ The thing about quotes on the internet is that you cannot verify their validity. - Abraham Lincoln
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05-14-2005, 11:12 PM	#7
wendybeth Nevermind Join Date: Jan 2005 Posts: 7,847	Tori wants to know why you are cheating....lol. (I told her I thought this was for school). __________________
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05-15-2005, 10:17 AM	#10
BarTopDancer Prepping... Join Date: Jan 2005 Location: Here, there, everywhere Posts: 11,405	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. __________________ Spork is the new MacGyver Postcards From My Edge
	Submit to Quotes