Question

cos(3x)=-1 using appropriate inverse trigonometric expression write and equation that defines the value of 3x

solve this equation to find all possible values for angle 3x


please help do not know where to start

Answer 1

\[let \ \theta=3x\\cos(\theta)=-1\]what are the solutions for this?

Answer 2

idk

Answer 3

please help t

Answer 4

then you need to memorize the unit cirle

Answer 5

circle*

Answer 6

ok

Answer 7

you should know all the values of x that make this true
cos(x) = -1

Answer 8

its at
\[\{...-3\pi,-\pi,\pi,3\pi,.......\}\]
so
\[3x=\pi+2\pi*k \ \text{where} \ k\in \mathbb{Z}\]

Answer 9

so k = {...-4,-3,-2,-1,0,1,2,3,4....}

Answer 10

thanks

Answer 11

np. memorize the unit circle. you really cant get by in this class without it.

Answer 12

okay i will

Answer 13

http://www.youtube.com/watch?v=OBmhgiLi77k

this might help

Answer 14

thank you!!

Answer 15

np

Answer 16

this is the first part, with the inverse function
\[3x=\cos^{-1}(-1)+2\pi k\]