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February 21st, 2014, 09:19 AM   #1
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if sin(theta)= -.1234 find (theta) in [-4pi,pi]

If sin(theta)= -.1234, find all (theta) in [-4pi,pi] that make this equation true.
What I have so far:
sin is negative in QIII,QIV
sin^-1(-.1234)=-.1237

0 - .1237 = -.1237
-pi + .1237 = -3.0179
-2pi - .1237 = -6.4069
-3pi + .1237 = -9.2011

There's nothing from 0 to pi, and from -3pi to -4pi since I need where sin is negative?

Thanks for the help!
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February 21st, 2014, 11:35 AM   #2
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Re: if sin(theta)= -.1234 find (theta) in [-4pi,pi]


Hello, mauro125!

Correct!
Good work!

soroban is offline  
February 21st, 2014, 01:33 PM   #3
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Re: if sin(theta)= -.1234 find (theta) in [-4pi,pi]

Hey there. You can also use the identity to view things a little clearer.
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February 22nd, 2014, 04:57 PM   #4
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Quote:
Originally Posted by mauro125
. . . -3pi + .1237 = -9.2011
Incorrect. -3pi + .1237 = -9.3011 (after rounding to four decimal places).
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