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May 1st, 2017, 05:13 AM   #1
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trigonometry

IMAG0367_1.jpg

help with the question above
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May 1st, 2017, 09:03 AM   #2
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What is the symbol circled in yellow? It would help if you typed out the equations ...

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Last edited by skeeter; May 1st, 2017 at 09:17 AM.
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May 1st, 2017, 09:36 AM   #3
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WHY have we yet not told this student to post CLEARLY
plus show his work?
All his posts so far show no work...

May I?
Jeho, please show CLEAR attachments PLUS your work.
Thank you in advance.
NOTE: your handwriting is worse than mine!
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May 6th, 2017, 10:01 PM   #4
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$\cos(\frac{\pi}{4}-\theta)=\frac{AB}{AE}$
$\cos(\frac{\pi}{4}-\theta)=\frac{1}{2}(1+\sin 2\theta)$
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May 7th, 2017, 08:39 AM   #5
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AE = AB/(AB/AE) = a/cos($\pi$/4 - ϕ)
AE² = 2a²/(2cos²(pi/4 - ϕ))
$\ \ \ \ \ \ \ \ $= 2a²/(cos($\pi$/2 - 2ϕ) + 1) (because cos2θ ≡ 2cos²θ - 1)
$\ \ \ \ \ \ \ \ $= 2a²/(1 + sin(2ϕ))
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