Answer:
The Best Answer for Determine if the graph is symmetric about the x-axis, the y-axis, or the origin. r = 2 cos 5θ?
r = 2 cos(5T)
polar axis or x-axis:
replace T by -T
r = 2 cos(-5T)
Since cos is an even function, cos(-5T)=cos(5T)
equation unaltered.
Equation is Symmetric about the x-axis
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About y-axis: or the line T = pi/2
replace T by pi – T
r = 2 cos(5T)
r = 2 cos(5(pi-T))
cos(5pi-5T) = cos(5pi)cos(5T) + sin(5pi)sin(5T)
= -cos(5T)
r = -2 cos(5T)
Equation not the same
Not symmetric with respect to y-axis:
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origin:
replace r with -r
r = 2 cos(5T)
-r = 2 cos(5T)
r = -2 cos(5T)
Equation not the same
Not symmetric with respect to origin.