Calculations in Grapher

Joined
Nov 23, 2011
Messages
5
Reaction score
0
Points
1
Ive just found the Grapher app on my mac which i never knew i had. Having never used Grapher before, im trying to work out the answers to P4 x and P5 y using Grapher.
Is anyone able to give me step by step instructions to work this out? Cheers!

e086a674-dd33-4e5f-8537-9d895d684f59.jpg
 

BrianLachoreVPI


Retired Staff
Joined
Feb 24, 2011
Messages
3,733
Reaction score
124
Points
63
Location
Maryland
Your Mac's Specs
March 2011 15" MBP 2.3GHz i7 Quad Core 8GB Ram | Mid 2011 27" iMac 3.4 GHz i7 16 GB RAM 2 TB HDD
Why not just plot that circle and the intersecting line and then click on the intersection points to see what they are - if you don't want to do the math to get the answer. I've never really messed with grapher - as unfortunately I was out of school before all these cool little app were available. I would have loved to have some of this sw back then.
 

BrianLachoreVPI


Retired Staff
Joined
Feb 24, 2011
Messages
3,733
Reaction score
124
Points
63
Location
Maryland
Your Mac's Specs
March 2011 15" MBP 2.3GHz i7 Quad Core 8GB Ram | Mid 2011 27" iMac 3.4 GHz i7 16 GB RAM 2 TB HDD
Oh - and it looks like there's a Find Intersection function in grapher.
 

BrianLachoreVPI


Retired Staff
Joined
Feb 24, 2011
Messages
3,733
Reaction score
124
Points
63
Location
Maryland
Your Mac's Specs
March 2011 15" MBP 2.3GHz i7 Quad Core 8GB Ram | Mid 2011 27" iMac 3.4 GHz i7 16 GB RAM 2 TB HDD
This is what happens when I'm stalling before I go run.

bydefault2011-11-24at122754PM.png


If you select your equation for the line AND circle - grapher will give you the intersection points.
 

BrianLachoreVPI


Retired Staff
Joined
Feb 24, 2011
Messages
3,733
Reaction score
124
Points
63
Location
Maryland
Your Mac's Specs
March 2011 15" MBP 2.3GHz i7 Quad Core 8GB Ram | Mid 2011 27" iMac 3.4 GHz i7 16 GB RAM 2 TB HDD
Geez. I do the guy's homework problem for him and he doesn't come back? Oh well - learned a bit about grapher in the process - what a great free piece of software. Could seriously use a little better documentation though.
 
OP
S
Joined
Nov 23, 2011
Messages
5
Reaction score
0
Points
1
Hey, thanks for your help but how do you even begin to set that up in grapher? Can i get step by step instructions to get to that stage please. Cheers
 

BrianLachoreVPI


Retired Staff
Joined
Feb 24, 2011
Messages
3,733
Reaction score
124
Points
63
Location
Maryland
Your Mac's Specs
March 2011 15" MBP 2.3GHz i7 Quad Core 8GB Ram | Mid 2011 27" iMac 3.4 GHz i7 16 GB RAM 2 TB HDD
Well - I did this a few days ago - but it's pretty simple - and I realized after I did it that I could have done it even more simply. That was the first time I had ever used grapher. I'm assuming this is a homework problem of some sort?

It's probably easier if you tell me what part you don't know. I'm assuming you're familiar with the equation for a circle? Start with that. Get your circle graphed and we can go from there.

Edit: What I should say is that most of it was simple - figuring out how to draw a line between two points in a manner that would allow use of the Find Intersects function was a little more difficult.
 
OP
S
Joined
Nov 23, 2011
Messages
5
Reaction score
0
Points
1
No, not a homework problem of any sort. Its a puzzle ive been trying to work out for sometime now and a mate of mine told me the best way to work it out is in grapher. Now, ive never used grapher before and have no idea how to set this up. The points refer to geographic coordinates based on a geocaching type puzzle. Im not familiar with the equation of a circle sorry. Any help would be greatly appreciated! Cheers
 

BrianLachoreVPI


Retired Staff
Joined
Feb 24, 2011
Messages
3,733
Reaction score
124
Points
63
Location
Maryland
Your Mac's Specs
March 2011 15" MBP 2.3GHz i7 Quad Core 8GB Ram | Mid 2011 27" iMac 3.4 GHz i7 16 GB RAM 2 TB HDD
Well - I'm not sure I agree with your friend - even as I was trying to figure out how to use grapher - I kept thinking that just solving the equations would be quicker - but who knows - maybe now that I know how to do it in grapher - it might be quicker the next time I tried.

I'll go dig out the file and post the equations I used. You could actually not solve for y and just use the square form of the equation. I'm just used to things like Matlab etc where that wouldn't have worked.

bydefault2011-12-04at62840PM.png
 

BrianLachoreVPI


Retired Staff
Joined
Feb 24, 2011
Messages
3,733
Reaction score
124
Points
63
Location
Maryland
Your Mac's Specs
March 2011 15" MBP 2.3GHz i7 Quad Core 8GB Ram | Mid 2011 27" iMac 3.4 GHz i7 16 GB RAM 2 TB HDD
So - in a nutshell - I plotted the line, after first deriving the equation for that line from the two points. I plotted the circle using the standard equation for a circle.

Don't worry about that highlighted equation - that was where I was experimenting with plotting over a certain range. In this particular example, you'll have to highlight the top half of the equation for the circle, while holding cmd and then selecting the equation for the line -then you can use the find intersect function. You'll have to do that again for the bottom portion of the circle.
 
OP
S
Joined
Nov 23, 2011
Messages
5
Reaction score
0
Points
1
Hey, thats awesome! Thanks so much for posting the equations!! Any chance of pm'ing me the answers? Cheers
 

BrianLachoreVPI


Retired Staff
Joined
Feb 24, 2011
Messages
3,733
Reaction score
124
Points
63
Location
Maryland
Your Mac's Specs
March 2011 15" MBP 2.3GHz i7 Quad Core 8GB Ram | Mid 2011 27" iMac 3.4 GHz i7 16 GB RAM 2 TB HDD
Hey, thats awesome! Thanks so much for posting the equations!! Any chance of pm'ing me the answers? Cheers

There's always a chance :p but what about teaching a man to fish?? How about you PM me the answers you get? Or are you not really interested in learning to fish?
 

BrianLachoreVPI


Retired Staff
Joined
Feb 24, 2011
Messages
3,733
Reaction score
124
Points
63
Location
Maryland
Your Mac's Specs
March 2011 15" MBP 2.3GHz i7 Quad Core 8GB Ram | Mid 2011 27" iMac 3.4 GHz i7 16 GB RAM 2 TB HDD

BrianLachoreVPI


Retired Staff
Joined
Feb 24, 2011
Messages
3,733
Reaction score
124
Points
63
Location
Maryland
Your Mac's Specs
March 2011 15" MBP 2.3GHz i7 Quad Core 8GB Ram | Mid 2011 27" iMac 3.4 GHz i7 16 GB RAM 2 TB HDD
I'm assuming that's correct - I haven't checked the answers - I'll leave that to you.
 
OP
S
Joined
Nov 23, 2011
Messages
5
Reaction score
0
Points
1
Yes, that is correct. Ive replicated the equations and have learnt heaps by doing this! Thanks for your time and help! Much appreciated! Cheers
 

BrianLachoreVPI


Retired Staff
Joined
Feb 24, 2011
Messages
3,733
Reaction score
124
Points
63
Location
Maryland
Your Mac's Specs
March 2011 15" MBP 2.3GHz i7 Quad Core 8GB Ram | Mid 2011 27" iMac 3.4 GHz i7 16 GB RAM 2 TB HDD
Yes, that is correct. Ive replicated the equations and have learnt heaps by doing this! Thanks for your time and help! Much appreciated! Cheers


You're welcome. :)
 

Shop Amazon


Shop for your Apple, Mac, iPhone and other computer products on Amazon.
We are a participant in the Amazon Services LLC Associates Program, an affiliate program designed to provide a means for us to earn fees by linking to Amazon and affiliated sites.
Top