maths 2009 paper 1 question 4

[josemane]

please i need hel p with this one theres no way of getting 7pi , on the (ii)

 

[Zohaib Sherazi]

Sin 2x = -1/2

let 2x = w

sin w = -1/2

w = -1/6 pi (make sure your calculator is in radian mode)

now subtract the above answer from pi ( symmetry property)

=7/6 pi

we assumed earlier 2x = w

2x = -7/6 pi

x = -7/12 pi

.....Here you go.