unit 5 basic trigonometry

quick review:

two special triangles we must remember, useful when being asked to solve for theta.
this one's easy to remember... both corners are 45 degrees, and it's one-one - root (two)

you can come up with the angles as long as you remember the numbers, and where they are. you can just test for tan root (three) = 60. and you'll know to put the 60 across from the root (three).

this is useful when being asked to solve for questions involving a wheel, calculating # of revolutions, velocity, etc. (angular velocity)

 converting radians to degrees, or degrees to radians... this can be remembered by knowing that 180 degrees is equivalent to pi. then you just cancel out the pi to get degrees. or you can divide the degrees over 180 and multiply that by pi to get the amount in radians.

  this is a tan graph. the cotangent graph is the same, but shifted 90 degrees to the right(or left) and flipped along the x axis (so the arrows change signs (pos-> neg, neg->pos), and point in the opposite direction).

 this is a sine graph and a cosecant graph, csc is the inverse of sin so you can see it below:

out of the three main types of identities, reciprocol, quotient, and pythagorean, pythagorean is the hardest to remember! These are important to know, so that proofs will be MUCH easier and faster to solve.

this one is probably not on the exam, but it was talked about.. so maybe it'll be on the exam? if not, good to know! this is called the root mean square, and is used to find varying alternating currents.

question 10 is one i have trouble with (i know 9b is circled, but i solved it =D):

this is the equation i got for the application of a sin/cosine graph.... and it was right.

so why couldn't i solve this? i got a very large number.... 390ish mins. odd? where did i go wrong...?


ok so i found out.. that ... i was in either the wrong calculator mode (supposed to be in rad) OR i could have used 360 degrees instead of 2pi. =) problem solved.