Tolong bantuin bagaimana cara mengerjakan soal ini ???

cos x = 1/2√2 => cos x = cos 45
# x = @ + k . 360
=45 + k .360
utk k = 0 => 45
# x = -@ + k. 360
= -45 + k. 360
utk k = 1=> 315
hp(45, 315)