Question about sum and products of trig functions (1 Viewer)

[Commando007]

i dont get this
can someone plz explain it in detail
thanks

 

[integral95]

Basically when you expand the RHS ,(Product of trig functions) you end up with the LHS (sum of 2 trig functions).

This conversion is useful in many cases, e.g if you have to cancel out terms or using integration.

 

[frog1944]

Is this a result we can use? I remember in the New Senior Maths textbook, during conics it said how these results are not included in the course.

 

[Commando007]

dont really know man

 

[integral95]

I should tell you that it is NOT REQUIRED IN THE HSC to remember these formulas, should you have to use it, they either give it to you, or get you to prove it then use it in the next part.