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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Hi You are allowed to expand the RHS using the usual trig identities cos(a+b) and sin(a-b)
I still don't know how to do it.
On the right side Multiply both to get the RHS On the left side
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