Mathematics
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OpenStudy (anonymous):
Factor the algebraic expression below in terms of a single trigonometric function.
sin 2x + sin x - 2
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OpenStudy (anonymous):
@jim_thompson5910 Can you help me understand these?
OpenStudy (anonymous):
sin(2x) = 2sin(x)cos(x)
OpenStudy (anonymous):
Is the last term sin(x-2), or sin(x)-2?
OpenStudy (anonymous):
sin ^2x + sin x - 2 I think it means sin(x). It just has a space there.
jimthompson5910 (jim_thompson5910):
hint: let z = sin(x)
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jimthompson5910 (jim_thompson5910):
z^2 = sin^2(x)
jimthompson5910 (jim_thompson5910):
so,
sin^2(x) + sin(x) - 2
turns into
z^2 + z - 2
jimthompson5910 (jim_thompson5910):
hopefully you see how to go from here
OpenStudy (anonymous):
(sin(x)+2)(sin(x)-1)? @jim_thompson5910
jimthompson5910 (jim_thompson5910):
you nailed it
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OpenStudy (anonymous):
Awesome! I've got a few more I don't quite understand..
jimthompson5910 (jim_thompson5910):
ok I'll help with 2 more
OpenStudy (anonymous):
Find sin θ if cot θ = - 4 and cos θ < 0. This one is like the one we did earlier, but a little different. I have no idea what it is asking for.
jimthompson5910 (jim_thompson5910):
what is cot in terms of opp, adj, hyp?
OpenStudy (anonymous):
adj/opp
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jimthompson5910 (jim_thompson5910):
so
cot(theta) = -4 and cot(theta) = adj/opp
because -4 = -4/1, we know that
adj = -4
opp = 1
jimthompson5910 (jim_thompson5910):
Now draw a right triangle with that info and use it to find the hypotenuse
OpenStudy (anonymous):
sqrt17
jimthompson5910 (jim_thompson5910):
good
jimthompson5910 (jim_thompson5910):
now you can find sin(theta)
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OpenStudy (anonymous):
sqrt17/17?
jimthompson5910 (jim_thompson5910):
correct
OpenStudy (anonymous):
Awesome. Hang on. I working the next one.
OpenStudy (anonymous):
*I'm