Trig expression

A

Albi

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Can someone check if I have done this correctly?
 

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Albi said:
It is [MATH]\frac{1-2cos²\alpha}{sin\alpha\cos\alpha}[/MATH]
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You have not told us:

What did you need to do with that expression? - evaluate, simplify, prove equivalence to some other expression or something else?
 
Both the numerator and denominator are associated with "double angle identities":

cos(2x)= 2 cos^2(x)- 1 and
sin(2x)= 2 sin(x) cos(x)
 
HallsofIvy said:
Both the numerator and denominator are associated with "double angle identities":

cos(2x)= 2 cos^2(x)- 1 and
sin(2x)= 2 sin(x) cos(x)
Click to expand...
Yeah I can solve it also this way and I'll get the same result.Have you seen the photo that I published?
 
I spotted a mistake in your photo, and it looks like a "copying out" mistake because it's corrected in the next expression...

mistake.png

I would STRONGLY advise you to avoid copying your homework (presumably for neatness). Try to make your work readable the first time. This will help you in an exam situation where "copying time" is much better spent on starting the next question!

Other than that, well done!
 
Cubist said:
I spotted a mistake in your photo, and it looks like a "copying out" mistake because it's corrected in the next expression...

View attachment 21845

I would STRONGLY advise you to avoid copying your homework (presumably for neatness). Try to make your work readable the first time. This will help you in an exam situation where "copying time" is much better spent on starting the next question!

Other than that, well done!
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Further "conglomeration" is possible - and s/he had done it in the response #1.
 
Cubist said:
I spotted a mistake in your photo, and it looks like a "copying out" mistake because it's corrected in the next expression...

View attachment 21845

I would STRONGLY advise you to avoid copying your homework (presumably for neatness). Try to make your work readable the first time. This will help you in an exam situation where "copying time" is much better spent on starting the next question!

Other than that, well done!
Click to expand...
I am not sure what exactly you are talking about,but I swear that I have not copied my homework I was simply trying to solve the problem quickly and I have unconsciously changed cos²a to sin²a
I felt the obligation to explain myself even though I am not forced to do so.Anyway you believe what you want,if you think that was copied I can not do anything about it.
 
Albi said:
I am not sure what exactly you are talking about,but I swear that I have not copied my homework I was simply trying to solve the problem quickly and I have unconsciously changed cos²a to sin²a
I felt the obligation to explain myself even though I am not forced to do so.Anyway you believe what you want,if you think that was copied I can not do anything about it.
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Quite a rude response! It's a very reasonable assumption on my part that you've copied the work out when a mistake appears on one line and then mysteriously disappears on the next line. I was just offering well meant advice, not a personal criticism. At least I actually checked the work that you showed!
 
Cubist said:
Quite a rude response! It's a very reasonable assumption on my part that you've copied the work out when a mistake appears on one line and then mysteriously disappears on the next line. I was just offering well meant advice, not a personal criticism. At least I actually checked the work that you showed!
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Yeah but we're humans not robots everyone makes mistakes,it is normal.Sorry if I made you feel bad with my response!
 
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