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Jan 31st, 2008, 03:46 PM
#1
Thread Starter
Lively Member
Cos2A.. WTH?
Evening all,
Just began revising my Higher maths.. the night before the prelim. Wasn't smart - i know.
Ive come across a slight problem.. i have no idea how to do this question.
Solve these equations, correct to 1 decimal place where necessary, for 0<=x>=360.
5cos2x - cosx + 2 = 0
I have absolutely no idea how i go about these type of questions. If you could help me with this one i'll hopefully be able to do others.
Thanks,
-Allan
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Jan 31st, 2008, 06:01 PM
#2
Re: Cos2A.. WTH?
cos2x = 2cos2x -1
-> 10cos2x -cosx-3 = 0
-> (5cosx-3)(2cosx+1) = 0
I'm sure you can take it from here.
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Feb 1st, 2008, 07:35 AM
#3
Thread Starter
Lively Member
Re: Cos2A.. WTH?
Thanks. Got 1 of the questions in my exam and i aced it
-Allan
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Feb 2nd, 2008, 06:09 PM
#4
Junior Member
Re: Cos2A.. WTH?
Oh god the higher maths. I assume your Scottish as well. thank god I am only doing int2.
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Feb 2nd, 2008, 06:13 PM
#5
Thread Starter
Lively Member
Re: Cos2A.. WTH?
I am aye. Its rubbish. Failed it (Y) :P for a second year running tbh.
-Allan
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Feb 3rd, 2008, 05:45 AM
#6
Frenzied Member
Re: Cos2A.. WTH?
Come on? Higher isn't that bad? There is just a lot of memory work and problem solving? What I hate is that this year is the first year that we are doing multiple choice questions.... I despise them.
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