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1. How would you do this question?
Is there a method of doing it or do you just work it out in the head?
2. sin(a+b)= sinacosb+cosasinb

do it for b= 180 (t1) and b= 360 (t2)
3. (Original post by lorobolorolo)
How would you do this question?
Is there a method of doing it or do you just work it out in the head?
You should know that sin(a+180) = -sin(a)

And, of course (a+360) is no different to (a)
4. (Original post by TenOfThem)
You should know that sin(a+180) = -sin(a)

And, of course (a+360) is no different to (a)
How do you know that? Is that like a rule?
5. (Original post by lorobolorolo)
How do you know that? Is that like a rule?
It's basic: angle transformation formulas, reduction to the first quadrant. Search it in the math book
6. (Original post by lorobolorolo)
How do you know that? Is that like a rule?
yes it is
7. SinX is a periodic function with a period of 2π.

That means that sin(x) = sin(x+2π)
sin(x)= -sin(x+π)

Yes, it's a rule.
It's the same for cosx
8. (Original post by kostis12345)

It's the same for cosx

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