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October 21, 2025, 08:17:23 pm

Author Topic: Heinemann 2.11 relations and regions  (Read 580 times)  Share 

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macostar

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Heinemann 2.11 relations and regions
« on: April 25, 2014, 05:13:22 pm »
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Hi guys, I'm stuck on these two questions. Textbooks is Heinemann Exercise 2.11 Q7 and Q11.

keltingmeith

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Re: Heinemann 2.11 relations and regions
« Reply #1 on: April 25, 2014, 10:05:23 pm »
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For 7, there are quite a few different ways to write each. For d, you could use the intersection of two circles, but that would take a bit of guessing, so let's use a couple of rays.

So, first we need to find the angle that the line makes with the x-axis. Given the ratio , we can see that this angle is approximately 56.3 degrees. So, this gives us:



But there's two problems with this situation - it doesn't include the part of the line that goes down, nor the point (-2,0). So, we can find the part of the line that goes down by taking 180 - 56.3, and then we just need to include the point (-2,0). This can be written as:



For e, we have a very simple ray, such that it starts at the point (1,0) and makes an angle of 45 degrees. This gives us:



For the next two, you simply need to take the equations and - using a lot of algebra - simplify it like any other. Using the first equation as an example:




I would then suggest moving one of the roots to the other side, it will make things easier to work with. Have fun!