Submitted by Anonymous (not verified) on
Forums:
When using trigonometry identities/formulas eg. double angle formula and others proofs on step questions do we need to prove them before using them or can we just use them straight away?
Don't know if this makes sense.
You can use without proof
Submitted by stcs on
You can use without proof anything in the formula book, unless you are asked to prove it.
You should probably know the double angle formulae, and sin(A+B), but anything more obscure than that will very likely be given in the question if you are meant to use it .
Stephen