Question

how do i evaluate cos^(-1)(-r2/2)??

Answer 1

the inverse cosine for -45degrees is undef......?

Answer 2

question is not clear. looks like
\[\cos^{-1}(-\frac{r^2}{2})\]

Answer 3

it's the inverse cosine of negative root 2 over 2

Answer 4

oooh

Answer 5

you want a number whose cosine is
\[-\frac{\sqrt{2}}{2}\]

Answer 6

and that number has to be between 0 and pi
or 0 and 180 if you are working in degrees

Answer 7

right i follow the restriction on the range

Answer 8

degrees or radians?

Answer 9

just says evaluate. because it's given as -(sqrt2/2) i'm assuming rads

Answer 10

in any case it will be
\[\frac{3\pi}{4}\] or
\[135\]

Answer 11

look at unit circle on last page of trig cheat sheet. you will see that the first coordinate at
\[\frac{3\pi}{4}\] is
\[-\frac{\sqrt{2}}{2}\]

Answer 12

so that is your answer

Answer 13

so the inverse cosine function just tells me the angle associated with the arc length -sqrt2/2 ?