Ok the last question on those pages of question is this and i have got stuck and cant figure it out. I need to show that (ds=degrees) Sin(45ds+x) +cos(45ds+x) = sqaureroot2 cosx. Ok so i did left side first and changed it to. Sin45Cosy + Cos45Siny +Cos45Cosy - Sin45Siny Now what i want to do is divide out the CosY and Sin Y but even if i do that it doesnt make square root two and i dont know what to do from there. Can you help me solve this last practise question.