What are sine and cosine and how do I use them?

[JamesU]

I'm a 7th grade student, but I study more advanced topics. I'm learning about mechanics, but it asks for sin and cos(cosin). I don't know too much about sin and cos, so I was wondering if anyone could explain it.

 

[whozum]

Um, that's a hard one. Sin,cosin and tangent are used to express ratios of sides on a triangle.

Draw a right triangle, and label an angle between the horizontal side and hypotenuse.

The ratio of the side opposite (not touching) the angle to the hypotenuse is equal to the sin of the angle.

The ratio of the side adjacent (touching, but not hypotenuse) to the angle is equal to the cosin of the angle

The ratio of the opposite side to the adjacent side is the tangent of the angle.

Its also helpful to study the unit circle, but in my opinion you are way ahead of yourself.

 

[michael376071]

Here's some pictures to supplement what whozum said, can be very confusing at first. I'm guessing with mechanics you are looking at free body diagrams? Basically if you have a force, you can break it up into 2 other forces with trig functions, cos(theta)*force for one component, and sin(theta)*force for the other. Them added up with be the total magnitude of the force. Sounds great that you are interesting in science and math stuff so soon, but don't worry wrack your brain too much, you have plenty of time to learn this stuff