Question

how would i find this
cosx= root 3

i need the value of x?

Answer 1

then you need to know your basic trig angles; which is more memorization than anything else

Answer 2

its not one of the basic ones

Answer 3

theres a way to figure it out, but i can't remember what it is

Answer 4

if you believe it isnt basic; then you need to use a calculator or a trig table;

the answer is x = cos^-1(x)

Answer 5

arccos is another name for the inverse function

Answer 6

thats what i thought, so i have to do inverse trig to find it?

Answer 7

it would be a miracle if
\[\cos(x)=\sqrt{3}\]

Answer 8

yes; you have to "undo" the trig :)

Answer 9

when i put that in my calc it says error

Answer 10

because
\[-1\leq \cos(x) \leq 1\] for all x

Answer 11

then the answer is undefined ;)

Answer 12

yes it is not possible. the biggest cosine can be is 1 and the smallest it can be is -1

Answer 13

so in particular it cannot be
\[\sqrt{3}\]

Answer 14

this problem has to have an answer, it was f(x)=cosx [-pi/3 , pi/3]

Answer 15

don't try to find the inverse sine or cosine of anything bigger than 1 or less than -1

Answer 16

unless you left out something in the problem, the answer is undefined

Answer 17

that's the whole problem, but the integral evaluation of that can't be undefined

Answer 18

Math is full of problems that have no answer :)

Answer 19

Mevertheless, there are complex numbers whose cosines are sqrt(3)

Answer 20

if this is a complex variables class ineedhelp is taking i will eat my hat

Answer 21

From Mathematica 8\[x= \text{ArcCos}\left[\sqrt{3}\right]=0.+1.14622 i \]