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# C3 Trig Homework... Help me OUT!?!? WILL REP! watch

1. "Given that tan^2x = 2secx + 2 find the possible values of cos x (which I worked out to be 0?)"

ANYWAY the bit i cant do is this "Hence find the values of x, 0<x<360, which satisyfy the equation tan^2x = 2secx + 2

2. Hint: What does tan^2x+1 equal? Use this and you've got yourself a quadratic
3. (Original post by tengil)
Hint: What does tan^2x+1 equal? Use this and you've got yourself a quadratic
yh i got sec^2x - 2secx + 1 = 0 and which gives (secx-1)(secx-1)???
4. (Original post by Greeze Geez)
yh i got sec^2x - 2secx + 1 = 0 and which gives (secx-1)(secx-1)???
You have made a mistake with this constant.
5. (Original post by Mr M)
You have made a mistake with this constant.
Oh yeah, is it sec^2x - 2secx -3 = 0??
6. (Original post by Greeze Geez)
Oh yeah, is it sec^2x - 2secx -3 = 0??
yes
7. is cos x therefore equal to 1 or -1/3 then??
8. (Original post by Mr M)
yes
is cos x therefore equal to 1 or -1/3 then??
9. (Original post by Greeze Geez)
is cos x therefore equal to 1 or -1/3 then??
10. (Original post by Mr M)
oh my bad, school boy error, i have x to equal 180, 70.5 and what else?? the quadrant i didnt learn in c2 :/
11. (Original post by Greeze Geez)
oh my bad, school boy error, i have x to equal 180, 70.5 and what else?? the quadrant i didnt learn in c2 :/
You don't need to learn quadrants. Stuff like that is for amateurs. To find the other solution for cos x, subtract your answer from 360 degrees.
12. (Original post by Mr M)
You don't need to learn quadrants. Stuff like that is for amateurs. To find the other solution for cos x, subtract your answer from 360 degrees.
Mr. M you are a GENERAL, much love for helping me, likewise 2 every1 helping..

Thanks, will rep when i can..
13. (Original post by Greeze Geez)
Mr. M you are a GENERAL, much love for helping me, likewise 2 every1 helping..

Thanks, will rep when i can..
The thank you was enough (you have zero rep power anyway!).
14. (Original post by Mr M)
The thank you was enough (you have zero rep power anyway!).
Hence the "when i can"... could you help me on this question... no else will reply http://www.thestudentroom.co.uk/show...0#post27907490 ??????

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Updated: September 30, 2010
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