Question

What is the approximate value of if Theta if cos Theta=8/15?

Answer 1

Hint:

if cos(theta) = 8/15

then theta = arccos(8/15) or theta = -arccos(8/15)

Answer 2

how do you put arc

Answer 3

into a calculator?

Answer 4

above the "cosine" or "cos" key is the \(\Large \cos^{-1}\) symbol, see this?

Answer 5

oh so arccos means cos-1?

Answer 6

yes, \(\Large \cos^{-1}\) means "inverse cosine"

Answer 7

inverse cosine = arccosine

Answer 8

so you would hit "2nd" then "cos"

then type in 8/15

then close off the parenthesis group

Answer 9

and hit enter

Answer 10

i got 1.00

Answer 11

but its not a answer choice?

Answer 12

make sure you're in degree mode

Answer 13

do you know how to change from degrees to radians and vice versa?

Answer 14

i got 57.76

Answer 15

me too

so that's one value of theta

Answer 16

another value of theta is -57.76

Answer 17

one of the answer choices is 58 so this would be the answer correct?

Answer 18

bc it says approximately

Answer 19

yeah that's close enough

what do the other ones say?

Answer 20

32
28
62
48

Answer 21

ok so it's 58 then

Answer 22

thanks

Answer 23

there are infinitely many of such values, but none of them are listed (except for 58 of course)

Answer 24

np