Summary
Use SOHCAHTOA to remember the definitions of sinθ, cosθ, and tanθ.
sinθ =
cosθ =
tanθ =
A vector is a quantity that has a direction as well as a magnitude.
Add vectors by connecting vector arrows tip to tail and connecting the
exposed tail to the exposed tip. The vector formed is the sum of the other
vectors.
Because A − B = A + (−B), you can subtract a vector by multiplying it by −1
(flipping the point of the arrow to the opposite end) and adding the resultant
vector to the other.
You can also add or subtract vectors by adding or subtracting their
components.
Multiplying a vector by a positive scalar creates a vector in the same
direction. Multiplying a vector by a negative scalar creates a vector in the
opposite direction.
To find the magnitude (length) of a vector, you cannot simply add the lengths of
the other two vectors. Resolve the vectors into horizontal and vertical
components and use the Pythagorean theorem.
