#Trigonometry

30 messages · Page 1 of 1 (latest)

dull reef
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Y = 2sinx/(1+cosx+sinx)
Z=(1-cosx+sinx)/(1+sinx)
Options are:
1)z= 1-y
2)z= 1+y
3)z= 1/y
4)z=y
I just need a little push to understand what to do here

onyx egretBOT
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drifting sun
dull reef
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Done

drifting sun
dull reef
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One minute

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Now what am I supposed to do?

drifting sun
# dull reef

That difference of squares in the denominator isn't quite correct. It should be (1 + sin(x))^2 - cos(x)^2.

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Also, don't expand anything in the numerator yet. You'll see why a bit later.

drifting sun
dull reef
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Breaking 1+sinx^2 will give sin²x+ cos²x +2sinx -cos²x
Or do I use half angle formula to simplify 1+sinx?

drifting sun
dull reef
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sin²x

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Ah

drifting sun
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Right, so that becomes 2sin(x)^2 + 2sin(x). And what can we do next?

dull reef
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Do we separate the terms?

drifting sun
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What do you mean?

dull reef
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Ah oops

drifting sun
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Wait, no.

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As I said, don't expand anything in the numerator. We have:
y = 2sin(x)/(1 + cos(x) + sin(x)) = 2sin(x)(1 - cos(x) + sin(x))/((1 + sin(x))^2 - cos(x)^2) = 2sin(x)(1 - cos(x) + sin(x))/(2sin(x)^2 + 2sin(x))

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What can we do from here?

dull reef
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Denominator 2sinx we take out?

drifting sun
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Yeah, nice!

dull reef
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Legsoooo

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Okay got it thank you so much

drifting sun
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Nice, you're welcome!

dull reef
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+close