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Hi...thanks I got everything right except the last part...when we solve 3@, we are supposed 6 answers but according to the marking scheme, only 3 answers are accepted. Why so? Or, is it because some of the answers are the same? Plz, can you see the question again?It's hard to copy paste pheta everytime, I'm using pheta=@ ok?
sin (2@+@)= sin2@cos@+ cos2@sin@ -------1
This you get in formula sheet.
Then what is sin2@ and cos2@?
sin 2@= 2sin@cos@
cos 2@= 1-2sin^2 @
Replace in first equation
2sin@cos@cos@ +(1-2sin^2 @)sin@
2sin@cos^2 @+(1-2sin^2 @)sin@
----------->cos^2 @= 1-sin^2 @
2sin@(1-sin^2 @)+ (1-2sin^2 @) sin@
2sin@-2sin^3 @+ sin@ -2sin^3 @
=3sin@ -4sin^3 @
Easy? It's all in the formula sheet you are given, you just have to substitute.
For part 2, Relatively easy you just replace x by what is given and simplify.
For part 3, solve sin 3@= 3/4
you get valueS of @ and replace in x= 2sin@/3^0.5
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