Question

Question #7f0cc

Answer 1

`x = arctan(-2/7)+pin ~~ 0.2783 + pin`

Explanation:

`2cos(x)+7sin(x)=0`

`=> 7sin(x)=-2cos(x)`

`=> sin(x)/cos(x) = -2/7`

`=> tan(x) = -2/7`

`=> x = arctan(-2/7)+pin, n in ZZ`

`~~0.2783+pin`

Note that we add `npi` to account for `tan(x)` being periodic with a period of `pi`, thus `tan(arctan(-2/7)) = tan(arctan(-2/7)+pi)=tan(arctan(-2/7)+2pi) = ...`