circular functions

[starbuckscoffee]

1. for pi<a<(3pi/2) with cos a = -sinb where 0<b<(pi/2), find a in terms of b.

2. for pi<a<(3pi/2) with sin a= -sinb where 0<b<(pi/2), find a in terms of b

3. for pi<a<(3pi/2) with cos x= -sin(pi/6), find the value of x (do not evaluate sin (pi/6)

[Mao]

use this property:



and these symmetry properties:

[dcc]

For an angle in the third quadrant, we know that:

Appling this to our situation:







The other two you should try yourself, but the very same process can be applied (be careful to consider the quadrant of the angles)

[starbuckscoffee]

use this property:



and these symmetry properties:

i'm a little confused, how does that help?

[Mao]

for 1:



now, this is really not within the right quadrants, so we manipulate it:

[starbuckscoffee]

......  where did the -a  come from?

[Mao]

[bucket]

this stuff isn't easy to explain unless it's done visually :S
all this symmetry shit has got to do with the unit circle.

[Glockmeister]

It's funny. This is one of the things in Methods I constantly forget.

[excal]

And where the cheat sheet is a godsend.

[Mao]

And where the cheat sheet is a godsend.

you meant the cheat OMG UNLIMITED PAGES BOUND NOTES!!!!