Trig q (1 Viewer)

[xibu34]

Could anybody help me with question 8a ? The book gives no explanation on how to simplify these so I don’t really know where to start.

 

[Deem_Skills]

do u know your double angle formulae?

sin2x = 2sinxcosx = 2cosxsinx

in this case, x = 3x

so 2cos3xsin3x = sin2(3x) = sin6x


If say the sin3x was replaced with sin3y, you'd have to use your products to sums so its sometimes a bit confusing but if the variables are the same, its double angle and if they're different, it's products to sums