1.

Given that y=2 x - 3 sin x, find an expression for in terms of cos x and then find .

2.

The diagram shows an isosceles triangle ABC inscribed in a circle of radius r cm and centre atO. Given that = radian and ADC = radians,showthat area , S , of triangle ABC is given by S = sin 2 (1+ cos 2 ).

for the first question, what i tried to do:

= 6( x)( x) - 3 cos x

=3 cos x [ 2 x cos x -1]

then.....how do i continue to simplify it?the answer is 3 cos x(1- 2 x)......

for question 2 ....

AB=

S

= ( )( )( )sin 2

=( ) sin 2

and......then....how do i simplify it to sin 2 (1+ cos 2 )....??? is my working correct in first place???

any help is much appreciated. thanks in advance.