Nathan's Blog

The concept that I understood the best this week was from 7-1.


Converting degrees to radians: degrees X PI/180


Ex. 120 degrees to radians= 120 X PI/180= 120PI/180= 2PI/3


Converting radians to degrees: radians X 180/PI


Ex. PI/15 to degrees= PI/15 X 180/PI= 180/15= 12 degrees


The other concept that I really understood was reference angles.

1.) Determine which quadrant that angle is in.

2.) Figure out if the function is positive or negative.

3.) Subtract 180 degrees from that certain angle until its absolute value is between 0 & 90

4.) If you end up with a trig chart angle, plug it in. If you didn't, then leave it alone or plug it into your calculator.



Here are the trig chart angles: 0 degrees= 0, 30 degrees= PI/6, 45 degrees= PI/4,

60 degrees= PI/3, and 90 degrees= PI/2.



Ex. sin 520 (HINT: You can subtract 360 from the given angle to get it between 0 & 360 so that it is easier to determine which quadrant the angle is in.)



520-360=160, so it is in Quadrant II.



sin is related to the Y axis, so in Q II, sin is positive.



Now you must subtract 180 from 520 until the absolute value is b/w 0 & 90.



520-180-180-180= -20

Since you want absolute value, you ignore the negative.



So your final answer is: sin20 degrees.



Those were the best two concepts that I understood, but the word problems were pretty easy too. The five trig functions were understandable, but it took me a while to get used to working them. So, for the most part, advanced math is somewhat easy, but then it isn't. This blog was also easier than I thought. This will probably be the easiest week of math this year, because it is bound to get tougher. BYE