Question

find all values of x in the interval [0,2pi] that satisfy the equation. 10cos(x)-5=0

Answer 1

solve for cos(x) and it should be apparent.

Answer 2

if you know the unit circle, that is.

Answer 3

10cosx-5=0 ---> 5(2cos x -1)=0
5=0 ; 2cos x -1 = 0 ---> cos x = 1/2 ----> x = cos^-1(1/2), which is pi/3. Right?

Answer 4

is that the only one in the interval?

Answer 5

along with 4pi/3. Correct?

Answer 6

not that one

Answer 7

5pi/3

Answer 8

there you go! great job!

Answer 9

thanks. I was rather unsure

Answer 10

trust yourself and check to be sure.