Show that sin S - sin T = 2.cos (S + T / 2) .sin (S - T / 2)

(By the way, am I right in saying that you are not allowed to expand the RHS when the question asks to 'show'?)

Thanks !

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- March 7th 2009, 02:14 AMnoobonastickDouble Angle Question
Show that sin S - sin T = 2.cos (S + T / 2) .sin (S - T / 2)

(By the way, am I right in saying that you are not allowed to expand the RHS when the question asks to 'show'?)

Thanks ! - March 7th 2009, 02:33 AMrunning-gag
Hi

You are allowed to expand the RHS using the usual trig identities cos(a+b) and sin(a-b) - March 7th 2009, 12:56 PMnoobonastick
I still don't know how to do it. (Crying)

- March 7th 2009, 01:09 PMrunning-gag
On the right side

Multiply both to get the RHS

On the left side