find the exact value of sin 2 pi/3 (1 Viewer)

frippyful · Jan 18, 2012

i am studying at the moment and i got the question:
find the exact value of sin 2 pi/3
the answer is root 3/2. i looked at the worded solutions, but i still don't get how the answer is achieved. maybe i missed it at school.
could someone please explain it to me
thanks guys
i didn't know how to get the pi symbol and square root sign, so if you're confused, sorry

nightweaver066 · Jan 18, 2012

$\pi $ radians$ = 180^o$

Definition of a radian: a unit of angle, equal to an angle at the center of a circle whose arc is equal in length to the radius

$\frac{2\pi}{3} = 120^o$

$sin120 = sin60 = \frac{\sqrt{3}}{2}$ by the table of exact values.

Shouldn't convert the radians in to degrees when doing these questions though, just understand that $\pi = 180 ^o$ .

Since it's in the second quadrant, $sin(\pi - \frac{2\pi}{3}) = sin\frac{\pi}{3} = \frac{\sqrt{3}}{2}$

frippyful · Jan 18, 2012

nightweaver066 said:
$\pi $ radians$ = 180^o$

Definition of a radian: a unit of angle, equal to an angle at the center of a circle whose arc is equal in length to the radius

$\frac{2\pi}{3} = 120^o$

$sin120 = sin60 = \frac{\sqrt{3}}{2}$ by the table of exact values.

Shouldn't convert the radians in to degrees when doing these questions though, just understand that $\pi = 180 ^o$ .

Since it's in the second quadrant, $sin(\pi - \frac{2\pi}{3}) = sin\frac{\pi}{3} = \frac{\sqrt{3}}{2}$

thanks so much for your explanation. i still didnt get it at first, but now i remember. you know. holidays. it really rusts my brain

find the exact value of sin 2 pi/3 (1 Viewer)

frippyful

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nightweaver066

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frippyful

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