Question 808518
I suspect you have a typo.
The typical problem would give you the value of sine or cosine, plus an extra clue,
and would ask you to find put all that.
With an extra clue, such as sin(t)>0,
you would be able to know both sin(t) and cos(t),
and then you would use those values and the trigonometric identities to find the half-angle and double-angle values.