i'll tell u the logic &u do it u'll get it.

 

just convert them into cos

 

(eg sin90=cos0)

&multiply & divide with 2(sinx)

 

x is the lowest angle of the cos

 

it will b sin2a form

 

so multiply & divide only with 2 in next two

 

at last u wil get intosin & cancelled

i cant give u  whole solution because itz lengthyyyyyyyyyy..............