SOLUTION: Hi! If you could show you work for this that would be great. What is the exact value of sin pi/3 as found on the unit circle?

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Question 1064795: Hi! If you could show you work for this that would be great.
What is the exact value of sin pi/3 as found on the unit circle?

Found 3 solutions by Alan3354, KMST, ikleyn:
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
Look up the unit circle.

Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
As you know the circumference of a circle of radius R is 2pi%2Ar.
For a r=1 , it would be 2pi .
So 2pi is the length of the unit circle circumference,
and the measure, in radians of the 360%5Eo angle
that is a whole sweep around the unir circle.
Half of that, p%A1 , is the measure of the angle that you know as 180%5Eo ,
and pi%2F3 in radians corresponds to
180%5Eo%2F3=60%5Eo .
Think of triangle with three 60%5Eo angles.
It is an equilateral triangle.
Here is such a triangle inside the unit circle:
Its altitude is h=sin%2860%5Eo%29 ,
or (if we measure angles in radians)
h=sin%28pi%2F3%29 .
The altitude divides the equilatetal triangle
into 2 right triangles.
The measure of the legs of those right trianglrs
are h and 1%2F2 .
The hypotenuse measures 1 .
According to the Pythagorean theorem,
h%5E2%2B%281%2F2%29%5E2=1%5E2
h%5E2%2B1%2F4=1
h%5E2=1-1%2F4
h%5E2=3%2F4
h=sqrt%283%2F4%29=sqrt%283%29%2Fsqrt%284%29rsqrt%283%29%2F2 .
So, sin%28pi%2F3%29=sqrt%283%29%2F2 .

Answer by ikleyn(52878) About Me  (Show Source):
You can put this solution on YOUR website!
.
On unit circle see these links
https://en.wikipedia.org/wiki/Unit_circle
https://en.wikipedia.org/wiki/Unit_circle

and

https://en.wikipedia.org/wiki/Unit_circle#/media/File:Unit_circle_angles_color.svg
https://en.wikipedia.org/wiki/Unit_circle#/media/File:Unit_circle_angles_color.svg


You MUST KNOW and MEMORIZE / REMEMBER it as the multiplication table.