Mathematics
14 Online
OpenStudy (anonymous):
verify each identity
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OpenStudy (anonymous):
OpenStudy (anonymous):
@ganeshie8
OpenStudy (anonymous):
@satellite73
Directrix (directrix):
Post which identity you want to do.
OpenStudy (misty1212):
HI!!
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OpenStudy (misty1212):
not that easy to read sideways is it? let me turn my head and see if i can figure one out
OpenStudy (anonymous):
sorry it's number 16 @Directrix
OpenStudy (anonymous):
\[\csc \theta+\cot \theta= \frac{ \sin \theta }{ 1-\cos \theta }\]
OpenStudy (misty1212):
oh ok mostly this usually algebra
lets see how far we get doing that
OpenStudy (anonymous):
is it fine to work with the left side?
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OpenStudy (anonymous):
which side is that for?
OpenStudy (misty1212):
that is the left side, i put \(\cos(x)=a, \sin(x)=b\)
OpenStudy (misty1212):
alas it is a mistake, dang
OpenStudy (misty1212):
\[\frac{1}{b}+\frac{a}{b}=\frac{1+a}{b}\]
OpenStudy (anonymous):
is that like an equation to use or did you make that up to assit the problem?
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OpenStudy (misty1212):
so the left side is \[\frac{1+\cos(x)}{\sin(x)}\] and the right is
\[\frac{\sin(x)}{1-\cos(x)}\] now these are equal, but we have to show it some how
OpenStudy (misty1212):
it is easier to see with letters rather than sine and cosine
makes the algebra easier
also makes writing it easier
most of it is algebra
OpenStudy (misty1212):
now if you want to turn
\[\frac{1+\cos(x)}{\sin(x)}\] in to
\[\frac{\sin(x)}{1-\cos(x)}\] you can do it by multiplying top and bottom by \(1+\cos(x)\)
OpenStudy (misty1212):
dang another typo
multiply by \(1-\cos(x)\)
OpenStudy (misty1212):
\[\frac{1+\cos(x)}{\sin(x)}\times \frac{1-\cos(x)}{1-\cos(x)}=\frac{1-\cos^2(x)}{\sin(x)(1-\cos(x)}\]
\[=\frac{\sin^2(x)}{\sin(x)(1-\cos(x)}=\frac{\sin(x)}{1-\cos(x)}\]
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OpenStudy (anonymous):
i'm a little confused so we're working with the right side
OpenStudy (anonymous):
?
OpenStudy (misty1212):
no turned the left in to the right
OpenStudy (misty1212):
you want me to try and write it in one line?
OpenStudy (anonymous):
csc=1/sin
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OpenStudy (anonymous):
i'm trying to take it step by step, tell me if i'm getting info wrong. so frist you looked at csc right?
OpenStudy (anonymous):
which is 1/sin?
OpenStudy (anonymous):
then you looked at cot which is cos/sin?
OpenStudy (misty1212):
right
OpenStudy (misty1212):
then added them up
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OpenStudy (misty1212):
which is easy because the denominators are the same
OpenStudy (anonymous):
Exactly, then you multipled it by (1-cos)
OpenStudy (misty1212):
right , top and bottom
OpenStudy (anonymous):
\[(1^2-2(1)(\cos \theta)+\cos \theta^2)/\sin \theta- \cos \theta \sin \theta\]
OpenStudy (misty1212):
dont multiply out in the bottom
leave in factored form
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OpenStudy (misty1212):
also \((1+a)(1-a)=1-a^2\)
OpenStudy (misty1212):
so your numerator is wrong
OpenStudy (anonymous):
what would the denominator be?
OpenStudy (misty1212):
\[\sin(x)(1-\cos(x))\]
OpenStudy (misty1212):
dont multiply out, leave it in factored form so you can cancel
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OpenStudy (anonymous):
cancel what?
OpenStudy (anonymous):
i got the answer
OpenStudy (misty1212):
ok good