Question

Find the exact real value of arccosThe quantity square root of two divided by two

Answer 1

find a number \(x\) where \(\cos(x)=\frac{\sqrt2}{2}\)
it should ring a bell

Answer 2

pi over 4?

Answer 3

yes

Answer 4

Thank you so much (:

Answer 5

do you know how i can do this
Use a calculator to find the approximate value of cos-1(0.55)

Answer 6

yw
make sure when you solve these that you pick the right number in the right range

Answer 7

depends on the calculator
i haven't used one since 2004
just use this
http://www.wolframalpha.com/input/?i=arccos%28.55%29
gives answer in both radians and degrees

Answer 8

I got it ! I just had to type the exact thing on my calculator , and for the first question I asked now its asking me for the exact real value of across The quantity square root of two divided by two , is that one across the actual cos on the unit circle?

Answer 9

yes

Answer 10

for arccosine pick the ones on the upper half of the unit circle, i.e. between \(0\) and \(\pi\)
for sine pick on the right between \(-\frac{\pi}{2}\) and \(\frac{\pi}{2}\)

Answer 11

so is it 11pi over 6 or 7 pi over 4 ? for the cos inverse of root 2 over two ?

Answer 12

oh no you had it right the first time
just \(\frac{\pi}{4}\)