How do you simplify #cos (2π/3 - a)#?
1 Answer
Jan 15, 2016
Explanation:
We know the cosine subtraction formula:
#cos(alpha-beta)=cosalphacosbeta+sinalphasinbeta#
Thus,
#cos((2pi)/3-a)=cos((2pi)/3)cos(a)+sin((2pi)/3)sin(a)#
#=-1/2cos(a)+sqrt3/2sin(a)#
This can also be written as
#=(sqrt3sin(a)-cos(a))/2#
