Question

cot(-4pi/3) find the exact value of the following expression without using a calculator

Answer 1

Use the unit circle.

Answer 2

If it makes it easier -4pi/3 is equivalent to -240 degree

Answer 3

trig is alot of memorizations ....

Answer 4

im getting up to that, but then its saying that to find cot, i have to take cos/sin, and cos is square rt of 3 and when i do sin its -1/2 and the correct answer is suppose to be neg square rt of 3/3.

Answer 5

the angle is whats important; all the trig functions are derived once you know the angle right?

Answer 6

-4pi (180)
----* ----- = -4(60) = -240
3 pi

Answer 7

360 - 240 = 120 degrees

Answer 8

sin(120) = sin(60) = sqrt(3)/2

cos(120) = -cos(60) = -1/2

cot = cos/sin

-1/2
-------- = -1/sqrt(3)
sqrt(3/2)

Answer 9

-1/sqrt(3) is a fine answer but alot of people believe that it is bad manners to have a sqrt(..) as a denominator so they rationalize it like this:

-1 sqrt(3) -sqrt(3)
----- * ------ = -------
sqrt(3) sqrt(3) 3

Answer 10

thank you, that explained it ten times better than the book ever could.

Answer 11

while im on the subject, do you have any good math online resources? so far, i have my calc textbook, a calc book from kaplan, calc for dummies. plus youtube videos lol. its so miserable to learn math without a teacher.

Answer 12

i taught meself calculus :) it is nice to have teacher to fill in the blanks yes.

If its practice you need; interactmath.com has alot of free practice problems

Answer 13

did you really? damn. mad props. some of it is easy, but some of it, forget about it. haha. thank youu