Week 2
Angle | Sin | Cos | Tan=Sin/Cos |
---|---|---|---|
30° | ![]() | ![]() | 1/√3 = √3/3 |
45° | ![]() | ![]() | 1 |
60° | ![]() | ![]() | √3 |
How To Remember?
To help you remember, think "1,2,3" :
- sin(30°) = √1/2 = 1/2 (because √1 = 1)
- sin(45°) = √2/2
- sin(60°) = √3/2
And cos goes "3,2,1"
- cos(30°) = √3/2
- cos(45°) = √2/2
- cos(60°) = √1/2 = 1/2 (because √1 = 1)
Soh Cah Toa
Cosine is equal to the x coordinate where this radius intersects the Unit circle
The Sine is equal to the y coordinate where the coordinate intersects the unit circle
y
Now, in this same circle, let us draw a right triangle
θ
θ rad.
P = (x, y)
•
y
x
1
Using the right triangle definitions of the trigonometric functions
we can write
sin θ =
opposite
hypotenuse
= y,
and
cos θ =
adjacent
hypotenuse
= x.
This week I was a little puzzled with what my teacher threw at me..... "THE UNIT CIRCLE"
The unit circle is a tricky concept to grasp but with Khan Academy's continuous assistance I am understanding the Unit Circle better and better each day
The unit circle is a tricky concept to grasp but with Khan Academy's continuous assistance I am understanding the Unit Circle better and better each day
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