Question

Find all solutions in the interval [0,2pi] without a calculator. Give exact answers. Need help on how to get the answer.
---> sin(cosx)=1

Answer 1

did you mean sin(x)cos(x) = 1?

Answer 2

as opposed to \(\large \bf sin[cos(x)]=1\)

Answer 3

no in my text book, it just says sin(cosx)=1

Answer 4

hmmm can you post a quick screenshot of it?

Answer 5

sure

Answer 6

would it just be no solution?

Answer 7

well
if we take what you said
we could firstly, to get the cosine out
get arcSine to both sides
\(\bf sin[cos(x)]=1\implies sin^{-1}(sin[cos(x)])=sin^{-1}(1)
\\ \quad \\
cos(x)=sin^{-1}(1)\impliedby {\color{brown}{sin^{-1}(1) \textit{ returns an angle} }}
\\ \quad \\
then
\\ \quad \\
cos^{-1}[cos(x)]=cos^{-1}[sin^{-1}(1)]\impliedby {\color{brown}{ cos^{-1}\textit{ expects a value, not an angle} }}\)

Answer 8

http://imgur.com/aButl8W picture of the textbook

Answer 9

eheheh

Answer 10

do we have to get a sore neck to view it?

Answer 11

hehe

Answer 12

lol sorry, the way imgur uploaded the photo...

Answer 13

I'd think there's a typo

Answer 14

it helps if the argument were enclosed in parentheses
to tell which is where

but I'd think is a typo

Answer 15

alright, so what would i do now?

Answer 16

well... you could try your amazing psychic powers and read your teacher's mind
now lacking that, you could try telekinesis to get your teacher's notes and see what he/she meant
lacking that you could just roll a couple of dice, but the answer is likely to be inaccurate

so, the better alternative, will be to email him/her for a clarification, or ask him/her on the next meeting

Answer 17

alright thanks for your help, but can you help me on one more problem?

Answer 18

sure, post anew, more eyes

Answer 19

okay ill close this and post a new one