What is the amplitude of
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Answer:
(x + 1)² + (y + 3)² = 16
Step-by-step explanation:
The equation of a circle in standard form is
(x - h)² + (y - k)² = r²
where (h, k) are the coordinates of the centre and r is the radius
Given
x² + y² + 2x + 6y - 6 = 0
Collect the x and y terms together and add 6 to both sides
x² + 2x + y² + 6y = 6
To complete the square
add ( half the coefficient of the x/ y terms )² to both sides
x² + 2(1)x + 1 + y² + 2(3)y + 9 = 6 + 1 + 9
(x + 1)² + (y + 3)² = 16
with centre = (- 1, - 3) and r = = 4
Imagine the unit circle. The cot(theta) is a line from (0,1) to (-4,1). Imagine it is part of a triangle with the origin (draw it!).
Then the hypotenuse length is √(1+4²) = √17.
The sine rule says that sin(90)/√17 must equal sin(theta)/4, and sin(90)=1, so
Then the hypotenuse length is √(1+4²) = √17.
The sine rule says that sin(90)/√17 must equal sin(theta)/4, and sin(90)=1, so