I am not really sure about questions 5 b,c, because there is no numbers, so i cannot really solve it. All I can do is to change the style of the question.

e.g. 5b) 3sin2x + 2cosx = 0 ->> 3(2sinxcosx) + 2cosx = 0 ->> 6sinx3cosx + 2cosx = 0 ... and that's how far i've got..

in 5c) i change cos2x to 1-sinx and that's all?

another one is question 7.. I think that t should equal 30 to get the lowest point (like on the clock, because there is 60 seconds) and my theory is imo kind of correct.. when i use t = 30 i get 1.13m, when i use 60 i get 2.86m and when i use 0 i get 2.86m so i think it is a highest point..

however.. when i use t = 45 i get 2.5m and if i use t = 15 i get 1.5m and this isn't correct, because these points should be at the same height. Also i used t = 31 and i get the lowest point 1m.. and i am completely confused now.. because if it is seconds.. then it should be divided for 60 parts (60 seconds).. but i don't know.. so i'm asking for help.

I couldn't upload the homework sheet here.. so i uploaded it on rapidshare/sendspace/turboupload:

http://www.sendspace.com/file/35w29o

http://d.turboupload.com/d/1417974/compound_angle_formulae.pdf.html

Thanks in advance