What is sin 0 if cos 0= √2/2 and 0 is in 0<0< π/2?

I’m really confused and need your assist me with this question i’ve never been taught

What is the maximum of the sinusoidal function

Aprobability experiment is conducted in which the sample space of the experiment is s={7,8,9,10,11,12,13,14,15,16,17,18}, event f={7,8,9,10,11,12}, and event g={11,12,13,14}. assume that each outcome is equally likely. list the outcomes in f or g. find p(f or g) by counting the number of outcomes in f or g. determine p(f or g) using the general addition rule.