How do you use the sum to product formulas to write the sum or difference #cos((3pi)/4)-cos(pi/4)#as a product?
1 Answer
May 24, 2017
Explanation:
The formula to use in this case is the difference of cosines formula:
#cos(alpha)-cos(beta)=-2sin((alpha+beta)/2)sin((alpha-beta)/2)#
In this case,
#cos((3pi)/4)-cos(pi/4) = -2sin(((3pi)/4+pi/4)/2)sin(((3pi)/4 - pi/4)/2)#
#= -2sin(pi/2)sin(pi/4)#
Final Answer
