Sunday, September 25, 2011

Finding trig values in equations

To find the vlaue of an angle in an equation you must first set and solve the equation. This takes back to algebra two rules for solving equations. You first get the trig function by its self then solve for it using calculator or trig chart. Then once you solve for it find two answers depending upon thw quadrant its in. Here is the rules for that:
1.-ve+180 (to go to second quadrant)
2.ve+180 (to go to third quadrant)
3.-ve+360 (to go to fourth quadrant)
To find out wich quadrants you need it depends on the function and if it negative or positive.

ex1. 8 sin + 2 = 4
First solve like equation. subtract 2 from 4. 8 sin =2
Then dive by 8. Sin = 2/8
Its not on trig chart so plug into calculator as an inverse to get an angle measure.
You get 14.476.
Sin is positive in first two quadrant. 14.476 is quadrant one. Now you must find two. Use rules above. So -14.476+180 = 165.524. Now take both answers and properly put them in degrees.
(14 degrees28'33", 165 degrees 31' 26")

ex.2 -2 cos + 1=5
-2 cos=4
cos=4/2 *negative is dropped till end
Calculator gives error when plugged in. This means your answer is undefined.

No comments:

Post a Comment