Geogebra Help

phrontister · 2014-04-01 03:34:48

a: 3x - y = -9

...which is the same as y=3x+9.

bobbym · 2014-04-01 03:39:25

That is correct.

What do those 3 coordinates really represent?

phrontister · 2014-04-01 03:50:58

Ordered pair solutions to the equation, verified by the straight connecting line.

bobbym · 2014-04-01 03:55:14

Clear the drawing area and in the input bar enter y = 3x + 9.

phrontister · 2014-04-01 03:58:57

It created a slider for x, and under 'Number' has X=1 and Y=12

Last edited by phrontister (2014-04-01 04:00:39)

bobbym · 2014-04-01 03:59:55

y = 3x + 9, sorry I was in caps lock.

phrontister · 2014-04-01 04:03:06

That gave a sloping straight line. Are the coordinates of any point along that line an ordered pair solution to the equation?

Last edited by phrontister (2014-04-01 04:06:17)

bobbym · 2014-04-01 04:07:52

Yep! Use the point on object tool and place a point on that line. Now move the arrow keys and read from the algebra pane the coordinates of the point. Each first number in the parentheses is an x and the second number is the y. Plug them into the equation and you will get a balanced equation. The right hand side lovingly called the RHS and the other side LHS. They will be equal algebraically, meaning they are solutions to the equation.

phrontister · 2014-04-01 04:12:47

Yes, that works...but I can't use the arrow keys to move the point to integer solutions.

Last edited by phrontister (2014-04-01 04:13:19)

bobbym · 2014-04-01 04:13:40

There is a way to do that using a slider. Are you able to move the point though?

phrontister · 2014-04-01 04:18:44

Yes...because I placed it away from the x and y axes, otherwise the point moves along the axis on which it is placed.

bobbym · 2014-04-01 04:24:55

That is because it became attached to the x or y axis instead of the equation we are interested in.

So, very loosely we can the say that the graph of an equation is the set of points that balance or solve the equation.

All clear to this point ( no pun intended ).

phrontister · 2014-04-01 04:27:57

Yes, I understand all of this so far...but I also understand what my eyelids are telling me, which is that they need to be in bed! I'll have to leave it here, to be continued...

Thanks.

bobbym · 2014-04-01 04:32:03

I knew you already knew but now we have established a common terminology and will get to circles and integrals next. Have a good night.

phrontister · 2014-04-06 22:40:20

Hi Bobby,

Ready to learn now about circles and integrals, but the going may be slow because this is all new territory for me...

Because of our time difference and my work commitments I may not be able to spend much concentrated time at it, though.

bobbym · 2014-04-07 05:15:23

Hi;

I am sorry, where did we leave off?

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#76 2014-04-01 03:34:48

Re: Geogebra Help

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