Find the slope of the tangent line to the polar curve r = 2 - sin(θ) at the point specified by θ = π/3.
Solution:
Given, r = 2 - sinθ is the polar equation.
Then, dr/dθ = -cosθ
x= r cosθ and y = r sin θ
Thus x = (2 - sinθ) cos θ
y = (2 - sin θ) sin θ
dy/dx= \(\dfrac{dy/dθ}{dx/dθ}\)
= [(d.(2 - sinθ) sin θ)/dθ]/ [(d.(2 - sinθ) cos θ)/dθ]
= [-cosθ sinθ + (2-sinθ )cosθ] / [-cosθ cosθ - (2-sinθ)sinθ ]
= [-cosθ sinθ + 2cosθ - sinθ cosθ] / [-cos2θ - 2sinθ + sin2θ]
= (2cosθ - 2sinθ cosθ) / (-(cos2θ - sin2θ) - 2sinθ)
= (2cosθ - sin2θ ) / (-cos2θ - 2sinθ )
The slope of the tangent at the point where θ = 𝜋/3 is
dy/dx at (θ =𝜋/3) = [2cos( 𝜋/3) - sin(2 𝜋/3)] / [-cos(2 𝜋/3) - 2sin( 𝜋/3)]
= [(2×1/2) - (√3/2)] / [-(-√3/2) - (2√3/2)]
=[(2- √3)/2] / [(1- 2√3)/2]
= (2-√3) / (1-2√3)
Therefore, the slope of the tangent at θ = 𝜋/3 is (2-√3) / (1-2√3).
Find the slope of the tangent line to the polar curve r = 2 - sin(θ) at the point specified by θ = π/3.
Summary:
The slope of the tangent line to the polar curve r = 2 - sin(θ) at the point specified by θ = π/3 is (2-√3) / (1-2√3).
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