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OpenStudy (markkboyy):
well i dont know what to say because i got
Simplify the expression.
−3
OpenStudy (brittany16):
what did you do to arrive to that conclusion?
OpenStudy (welshfella):
(sin Θ − cos Θ) − (sin Θ + cos Θ)2
= sin Θ - cos Θ - ( sin^2 Θ + cos^2 Θ + 2 sin Θ cos Θ}
Now sin^2 Θ + cos^2 Θ = 1 and
2 sin Θ cos Θ = sin 2Θ
- can you continue?
OpenStudy (brittany16):
no, i have no idea how to do this
OpenStudy (welshfella):
Oh - no need to use that final identity
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OpenStudy (welshfella):
well replace sin^2 Θ + cos^2 Θ by 1 then just simplify
OpenStudy (brittany16):
im still confused, what exactly am i simplifying
OpenStudy (welshfella):
sin Θ - cos Θ - ( sin^2 Θ + cos^2 Θ + 2 sin Θ cos Θ}
= sin Θ - cos Θ - ( 1 + 2 sin Θ cos Θ}
OpenStudy (welshfella):
now distribute the negative over the parentheses and you have the answer
OpenStudy (brittany16):
-1-2sin(theta)cos(theta)?
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OpenStudy (welshfella):
what happened to the first 2 terms?
OpenStudy (brittany16):
oh im sorry, let me retry
OpenStudy (welshfella):
- the distribution you did is correct
OpenStudy (brittany16):
wouldnt they just stay the same in front of what i did?
OpenStudy (welshfella):
of course
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OpenStudy (brittany16):
okay, thats not an answer choice though
OpenStudy (brittany16):
can it be further simplified?
OpenStudy (welshfella):
no
OpenStudy (brittany16):
im not sure whats wrong then
the answer choices are:
−sin2 Θ
−cos2 Θ
0
−2sin(Θ)cos(Θ) − cos(Θ) + sin(Θ) − 1
OpenStudy (brittany16):
is it the last one and its just written differently?
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OpenStudy (welshfella):
Yes
they could have changed the fist part to - 2 sine theta but chose not to.