- 6.4 homework is due Friday.
- Your 6.2 homework is returned:
- #12, p. 448 -- remember, sin goes with csc, cos with sec
- #28 -- need to evaluate the expression -- don't leave "tan(36)" in your answer
- #20 -- some of you messed up the hypotenuse -- it's got to be longer than either leg!
- #34 -- you needed to find both legs.
- Your 6.3 homework is returned:
- #4, p. 459 -- it's best to simply draw the angles.
Nonetheless, here's a strategy to put an angle into reference angle form (without drawing): add or subtract multiples of
(180 degrees)
(notice that this won't change the angular distance between the ray and the x-axis)
until the angle is acute (negative or positive).
Now make it positive.... Let's see if it works for these three angles: 120, -210, 780.
- #24 - draw!
- #47 - draw!
- #50 - draw! You can even use legs that are negative!
- #4, p. 459 -- it's best to simply draw the angles.
- at this point in our careers with the circular functions sine and cosine, we think of them as taking an angle and turning it into a number (between -1 and 1).
- Often we think of right triangles. Draw!
- Inverse
trig functions (e.g. arcsin -- or
-- and arccos -- or
) take numbers (between -1 and 1) and turn them into angles.