Question

how do you put these in a fraction or square root???
can someone tell me how?

i)sin120
ii)cos(-120)
iii)tan135
iv)sin300
v)cos270

thx :)

Answer 1

Use the unit circle

Answer 2

are the angles expressed in radians or degrees?

Answer 3

ill assume degrees;

Q2 sin(120) = sin(180 - 60) = sin(60) = sqrt(3)/2
Q3 cos(-120) = cos(180 + 60) = -cos(60) = -(1/2)
Q2 tan(135) = tan(180-45) = -tan(45) = -(1)
Q4 sin(300) = sin(360-60) = -sin(60) = -sqrt(3)/2
yaxis cos(270)= cos(3*90) = cos(90) = 0

Answer 4

all degrees

Answer 5

I thought so :) at my age you can never be to sure tho...

Answer 6

i dont get why you sqrt it tho :S
and whats the cos(3*90) and why did you put something about y axis?

soz :(

Answer 7

Q= quadrant that it ends up in which is important in order to determine whether or not the answer is a positive or negative.

The cosine funtion actually tells you the value of the x coordinate. At 270 degrees you are pointing straight down on the y axis and x=0 so cos(90)-straight up, or cos(270)-straight dwon, equals 0.

Answer 8

lol... "sqrt" is how I do square root :)

Answer 9

i know its the square root but why did you have to do that?
:S
clueless :(

Answer 10

It is the definition of sin and cos. If you draw a right triangle with a 60 degree angle and a 30 degree angle you end up with a hypotenuse of (2) and a leg that is equal to (1).

If we use the pythagorean theorum; x^2 + y^2 = r^2 we can find the length of the other leg.

x^2 + (1)^2 = (2)^2
x^2 +1 = 4
x^2 = 4-1
x^2 = 3 ; sqrt both sides
x= sqrt(3)

That is it in a nutshell. It is just what happens when trying to figure out the measurements of a triangle.

Sin = opposite leg/hypotenuse; sin(60) = sqrt(3)/2

Same thing for cosine; which is adjacent leg/hypotenuse for any given right triangle.