am i stupid (1 Viewer)

[synthesisFR]

in tutoring we learn that it could be +_ 4(sqrt5)/9
bc the cos can be fourth quadrant so sin would be negative
but in these questions they dont speicify a domain and just take the positive first quadrant solution
what do i follow? bc our tutor drilled it into our head that theres always* 2 solutions and if the q doesnt state domain u have to state both cases but this hsc question just had one?

 

[indeed]

I think it may have to do with the fact that cos-1 has a domain between 0 and pi (so only 1st and 2nd quad are you're options - and in this case it's 1st)

 

[synthesisFR]

I think it may have to do with the fact that cos-1 has a domain between 0 and pi (so only 1st and 2nd quad are you're options - and in this case it's 1st)

ogh yeah cuz u start with arcos so it has to be 1 or 2 quadrant
okay thx that makes sense i want to drop school rn i feel stupid

 

[indeed]

okay thx that makes sense i want to drop school rn i feel stupid

we all have those days