Determine two pairs of polar coordinates for the point (4, -4) with 0° ≤ θ < 360°.
Solution:
The polar coordinate can be written as (r, θ)
Where r is the radius
θ is the angle
The radius here is the hypotenuse of the right triangle formed.
r2 = x2 + y2
We can write it as
r = √(x2 + y2)
By substituting the values
r = √(42 + (-4)2) = 4√2
We know that
tan θ = y/x
Now by solving for θ
θ = tan-1 (y/x) = tan-1(-4/4)
As we know that, tan θ is negative in second and fourth quadrant.
In II quadrant, angle θ = 3π/4.
In IV quadrant, angle θ = 7π/4.
Let us consider positive value of r in IV quadrant .
Hence, polar coordinates points will be (4√2, 7π/4).
Let us consider negative value of r in second quadrant.
Hence, polar coordinates points will be (-4√2, 3π/4).
Polar coordinates points of (4,-4) are (4√2, 7π/4) and (-4√2, 3π/4).
Determine two pairs of polar coordinates for the point (4, -4) with 0° ≤ θ < 360°.
Summary:
The two pairs of polar coordinates for the point (4, 4) with 0° ≤ θ < 360° are (4√2, 7π/4) and (-4√2, 3π/4).
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