Hello
Using the formula
cos(2x) = 2cos²x - 1
I figured I would post this in here and hopefully get somebody who likes trig to help me through this.
Given that cos x = (3^.5) − 1, find the value of cos 2x in the form a +b(3^.5) ,
where a and b are integers.
Given that
2 cos (y + 30)= 3 sin (y − 30),
find the value of tan y in the form k 3 where k is a rational constant.
a bit of background here is that I am looking to take my high school maths certificate and I found out that well... Im rubbish at trig!
Hello, GregoryT!
We are expected to know the identity: .1) Given that: . ,
find the value of in the form , where are integers.
Then we have: .
. .
Given that: . ,
find the value of . . . in the form k 3 where k is a rational constant. . ??
We have: .
. .
. .
Multiply by 2: .
. .
. .
. .
. .
Therefore: .