Multiple-Angle Equation...4

[nycmathguy]

Section 5.5

 

[MathLover1]

2cos(x)( sin(x) -cos(x))=0

if 2cos(x)=0 =>cos(x)=0=>x=cos^-1(0)=2 π n + π/2 ,2 π n - π/2

if ( sin(x) -cos(x))=0=> x =π/6+ 2π n ,x= 5π /6+2π * n
solutions:
x=2 π n + π/2..............n element Z
x=2 π n - π/2.............n element Z
x=2 π n + (5 π)/6.............n element Z
x=2 π n + π/6.............n element Z

 

[nycmathguy]

2cos(x)( sin(x) -cos(x))=0

if 2cos(x)=0 =>cos(x)=0=>x=cos^-1(0)=2 π n + π/2 ,2 π n - π/2

if ( sin(x) -cos(x))=0=> x =π/6+ 2π n ,x= 5π /6+2π * n
solutions:
x=2 π n + π/2..............n element Z
x=2 π n - π/2.............n element Z
x=2 π n + (5 π)/6.............n element Z
x=2 π n + π/6.............n element Z

After all that work, I am wrong. This is sad. Here I am thinking that learning is taking place when maybe precalculus is not sinking into my head. Perhaps, I am in over my head with this course and textbook. I probably should go back to Algebra 1 and start from there. If not that far back, perhaps Algebra 2.

See link below.

Multiple-Angle Equation...3