Yo! Keith's here

Yesterday was a short class because its Wednesday and our pre-cal is in first subject, everyone was excited about the smart board and we should pick a wall where to put it.

anyways we discuss about solving the angle.

to solve for Θ

1st you need to determine the reference angle

2nd select possible quadrants using CAST rule

3rd check the interval given.

4th state values for Θ in degrees or radians.

like in our text book :)

Example:

given: cosΘ= -0.43214°

solution:cosΘ

= -0.43214°

Θ=cos^-1(0.43214) note: you don't need to put negative here

Θ=64.39655323° (note: Mr.P said that you should put all the numbers :p)

this will be your Ref. then use the CAST rule to identify what quadrant(s) it will be.

your cos is negative because of the -0.43214 and it will be on the QII and QIII, the

cos is negative on that quadrants. Follow the formula given.

QII: Rel.= 180°-Ref.

so 180°-64.39655323°

Θ=115.6034468°

QIII: Rel.=180°+Ref.

so 180°+64.39655323°

Θ=244.3965532°

Θ=115.6°,244.3° (note: Mr.P said that your answer should be on 1 decimal place)

if your not satisfied try to visit this Solving Trigonometric Equations

just a reminder to all that the iPhoto project is due tomorrow

ok? ;)