Question

How do you solve `2cos(2x+80)=1` for `0<=x<=pi`?

Answer 1

`125deg` and`170deg`

Explanation:

`2cos(2x+80)=1`
`cos(2x+80)=1/2`

The angle whose cos is `1/2` is 60

Draw the cosine graph ( I don't know how to do that on this)

The other angles whose cos is 60 are 330 and 450...etc

`2x+80=60` that gives x = -10 not in range
`2x+80=330` that gives x =125 that's ok
`2x+80=420` that gives x= 170 that's ok