Which relation is not a function?

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Explanation:

The plus/minus indicates we have two equations, and they are

If x is say x = 4, then y is both y = 2 and y = -2 at the same time.

A function is where any x input leads to exactly one and only one y output (assuming the x value is in the domain). Graphing out choice D shows that it fails the vertical line test. This is where a vertical line crosses through more than one point on the graph. For the other answer choices, it is impossible to draw a vertical line through more than one point on the graph, which visually shows they are functions.

9.55 degrees.

step-by-step explanation:

the given angle is

1 cycle is equal to 2π radians. so 4π will be equal to two cycles.

5.166667π-4π = 1.166667π

hence, this angle goes a little more than negative x axis.

1.166667π-π= 0.166667π

hence, the reference angle is 0.166667π radians.

1 radian = 57.2958 degrees

now, in degrees, this should be equals to 9.55 degrees.