Question 1000866
.
cos(x)*sin(x) = {{{1/2}}}*sin(2x).


It is well known trigonometry formula called double argument formula for sine.


Then your equation takes a form


{{{1/2}}}*sin(2x) = 0.84.


Multiply both sides by  2.  You will get


sin(2x) = 1.68.


But sine can not be greater than  1.  Contradiction.


<U>Answer</U>. &nbsp;The given equation has no solution.