I am very bad with trig, can anyone help me with a few problems?
How do I find the cos of 300 degrees without a calculator?
and the csc of 3pi over 2 w/o a calculator?
2007-01-13 17:18:08 · 3 answers · asked by Anonymous in Education & Reference ➔ Homework Help
300 = (360 - 60) = 2pi - 60.
This means cos 300 = cos(2pi - 60) = cos 60 = 1/2!
similarly cos 3pi/2 = cos (pi - pi/2) = -cos(pi/2) = -cos 90 = 0!
cos(2pi - 60) = cos 60 & cos (pi - pi/2) = -cos(pi/2) are got by applying quadrant rule. hope this solves ur problem!
2007-01-13 18:13:43 · answer #1 · answered by Neo 2 · 0⤊ 0⤋
well the cos of 300 is 1/2. because 60 120 240 and 300 degrees all have the same sines and cosines. the sines are root 3 divided by two and the cosine is 1/2. 30 150 210 and 330 degrees' cosine and sine are the opposite.
csc of 3 pi is just the 1/sin3pi
2007-01-14 01:42:47 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Try this link
http://en.wikipedia.org/wiki/Cosine
2007-01-14 01:30:26 · answer #3 · answered by Nikolas S 6 · 0⤊ 0⤋