1. Redo your differentiation, cause it's false.
Then there's a simple way of relating to .
2. The formula for AB is correct.
Start from it and compute AD and BD.
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 at O. Given that = radian and ADC = radians, show that 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.