# Compound anglesWatch

#1

Help with these please, i dont understand what the max/min are.

Thanks!
0
5 years ago
#2
the question is really after the amplitude of the expression. (to be precise, the lowest value and the highest value - the lowest will be the negative of the highest)

I will do a) just to demonstrate the idea.

We might be able to notice, straight away, that a) is of the form (here, A=x, B= Pi/6. In which case the amplitude is 1.

But, what if we didnt?

we use the fact that we have a cos function first, followed by a + sign separating terms to suppose that we have something of the form
where R is the amplitude.

We then expand this to read

so that, and from which,

Now,

so the actual expression is equal to:

Do this for b, c, and d, picking the most suitable form of cos/sin(A+/-B) opr the expression

for b) take out a factor of 3 first, and a factor of 4 out of d).
0
#3
(Original post by Hasufel)
the question is really after the amplitude of the expression. (to be precise, the lowest value and the highest value - the lowest will be the negative of the highest)

I will do a) just to demonstrate the idea.

We might be able to notice, straight away, that a) is of the form (here, A=x, B= Pi/6. In which case the amplitude is 1.

But, what if we didnt?

we use the fact that we have a cos function first, followed by a + sign separating terms to suppose that we have something of the form
where R is the amplitude.

We then expand this to read

so that, and from which,

Now,

so the actual expression is equal to:

Do this for b, c, and d, picking the most suitable form of cos/sin(A+/-B) opr the expression

for b) take out a factor of 3 first, and a factor of 4 out of d).
Ah, ok thanks.
0
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