Tag Archives: Sin
Sine and Cosine Stating Negative Angles
Let’s take a look at this pic below
Now as the angle x goes down and down toward 0, the side on the front of the angle also get shorten and shorten. When x goes negative the side in front of the angle point downward.
The side near the angle remain constant though.
As x goes down to exactly -x we got a congruent triangle except flipped outside down.
So the cosine remain the same, namely b/c. The sine is just the additive inverse. Before it’s a/c, now it’s -a/c.
Hence, we easily see sin(-x)=-sin(x) and cos(-x)= cos(x)
Sines and Cosines
Take a look at
the angle we’ll be discussing is x.
In front of the angle we see b
x is an angle between the tilted side and the other side. Well the tilted side is called the hypotenuse. In Indonesia we simply called them tilted side. You’ll learn math more easily if you know some Asian language.
sine also abbreviated as sin, as in screwing someone else hoes, is the ratio between the front side and the tilted side.
So, sin (x) = b/c