Can someone clarify this (1 Viewer)

[M@ster P]

Can some clear this up for me , I am just wondering if the trigonometry topic "Products as sums or differences" and "Sum or differences to products" is in the 3unit syllabus. If it is not does that mean that i would not get tested on it in the hsc.

Also is it useful to learn, even in the case that it is not in the 3 unit syllabus

 

[tommykins]

3unit exam test 2unit stuff as well.

i'd say learn it.

 

[vds700]

Can some clear this up for me , I am just wondering if the trigonometry topic "Products as sums or differences" and "Sum or differences to products" is in the 3unit syllabus. If it is not does that mean that i would not get tested on it in the hsc.

Also is it useful to learn, even in the case that it is not in the 3 unit syllabus

To answer your question, no, u dont need to know them for 3 nit (check pg 41 of the syllabus, up the top and you'll see).However, if u are thinking of doing 4 unit, then it is essesntial u learn them because they are used a bit in 4 unit.

 

[Slidey]

I wouldn't call it essential. It's a good idea, certainly, but I don't believe I've ever seen them tested in any official capacity.

 

[ronnknee]

They aren't really anything new. They are just expressions with the use of compound angles. I'd say, learn how to derive them, which isn't too hard.

eg.
sin (A + B) = sin A cos B + cos A sin A (1)
sin (A - B) = sin A cos B - cos A sin A (2)

(1) + (2)
sin (A + B) + sin (A - B) = 2 sin A cos B
Therefore, sin A cos B = 1/2 [sin (A + B) + sin (A - B)]

And other expressions can be derived similarly
No need to memorise

 

[M@ster P]

ok thanks for ur inputs