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# Need Help with Trig Problem: 4cosec^2x - cot^2x = k watch

1. "Show that the equation 4cosec^2x - cot^2x = k, where k =/= 4, can be written in the form sec^2x = (k-1)/(k-4)"

So far I got to 3 / (1- cos^2x) = k -1, I can't seem to see where the other k comes from - is it to do with the fact hat k =/= 4 somehow?

Any help much appreciated.

This is from a very recent AQA GCE maths paper, the mark scheme of which I don't have access to!
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2. (Original post by pencil_maniac)
...

Dividing throughout by :

Now use the fact that to finish off.
3. (Original post by pencil_maniac)
hat k =/= 4 somehow?
Oh, and it's good that you're inquiring into the conditions imposed in the question! In this case, we have since and we can't the denominator being , can we? So .
4. Thanks very much Zacken, I've got it now!
5. (Original post by pencil_maniac)
Thanks very much Zacken, I've got it now!
Great, good job!
6. Am I too late again ? ...
7. (Original post by TeeEm)
Am I too late again ? ...

that always happens to me as well...
whenever i see a maths thread... i am always like yeah i am gonna answer that but either you or Zacken are already ruling on the thread
8. (Original post by TeeEm)
Am I too late again ? ...
I'm going out tonight, have fun with the maths forum.
9. (Original post by Zacken)
I'm going out tonight, have fun with the maths forum.
Tonight I am off to bed early as I start teaching at 8 a.m. on Saturday ...
10. (Original post by TeeEm)
Tonight I am off to bed early as I start teaching at 8 a.m. on Saturday ...
...well that's unfortunate.

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Updated: February 26, 2016
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