Question

I need help please

Answer 1

a product is = to 0 if either term is 0, for example ab=0 when either a=0 or b=0

set each individual term = 0 and solve

Answer 2

So each term has to equal 0?

Answer 3

yeah. \(\cos(x)=0\\\cos(x)-1=0\)

Answer 4

So I would type cos(1/2)(cos(1/2)-1) in a calculator?

Answer 5

why a half?

Answer 6

That is one cos variables on the unit circle

Answer 7

https://www.mathsisfun.com/geometry/images/circle-unit-radians.gif

Answer 8

So do I type that into the calculator?

Answer 9

the way to read that is \(\cos(\dfrac{\pi}{2})=0\)

Answer 10

and so for cos x = 0, x=pi/2 +2npi

Answer 11

I don't get it

Answer 12

err pi n

Answer 13

what don't you get? the \(\pm\) is the period

Answer 14

I'm still confused...

Answer 15

basically, you have it right

Answer 16

ok, so I just type it in the way you said?

Answer 17

type what out? your work?

Answer 18

No into the calculator

Answer 19

oh, you should be using \(\cos^{-1}(x)\) or the \(arccos\) buttons

Answer 20

ok

Answer 21

and so for the first one, we have \(cos(x)=0\\arccos(cos(x))=arccos(0)\\x=arccos(0)\\x=\dfrac{\pi}{2}\)

Answer 22

ok, I think I have it now, thank you for the help

Answer 23

similarly arccos(1)=2pi

Answer 24

Thank you again for the help

Answer 25

anytime