Step 4 is correct.
Hi all,
To start with - the problem.
solve for
The working I've done so far.
1.
2.
3.
4. or
5.
6.
7.
Therefore, or
Which means that or
I'm just not sure if step 4 is correct. Can I simply ignore one of the options because is invalid?
Cheers.
you can't do that on step three you need to do the following:
3-3cos^2x+7cosx=5
take everything to the right hand side
3cos^2x-7cosx+5-3=0
3cos^2x-7cosx+2=0
now you have to factorise
i would replace the cos with y first
3y^2-7y+2=0
(3y-1)(y-2)=0
so
3cosx=1
cosx=1/3
or cosx=2
x=error
so x=70.53 or 289.47 (2dp)
and i have used x instead of theta