The question is stated more than a little ambiguously, but I presume you mean:
(i) the polar curve is given by : r = f(Θ) = 4 sin Θ.
[Without any mention of ' r ,' it's NOT a polar equation! It simply defines a function f(Θ) of Θ --- no big deal, but that's NOTHING to do with a polar equation. I'm afraid that the previous two responders just didn't recognize that.]
(ii) I also presume that the slope of the tangent is required with respect to the line Θ = 0, and NOT with respect to the polar curve itself.
In that case, the answer is d.) 3^(1/2). Here's why:
Let the tangent make an angle ' fi ' with respect to the radial vector. Then standard results (easily seen from a simple sketch) are:
(a) tan fi = r dΘ / dr ; and
(b) the angle the tangent makes with the line Θ = 0 is fi + Θ.
Now for the calculation:
If r = 4 sin Θ, then dr / dΘ = 4 cos Θ, therefore
tan fi = (4 sin Θ) / (4 cos Θ) = tan Θ (!)
Therefore fi = Θ = π/6. Thus the angle the tangent makes with the line Θ = 0 is fi + Θ = π/6 + π/6 = π/3. And tan π/3 = 3^(1/2), of course.
You already calculated your spinoff. Now, plug on your factor (0,0) and prepare that it yields a million/2, it is the slope of your tangent. Now, set the tangent equivalent on your function, i.e. x/2 = (2x)/... remedy this for x. Your ideas are then the x coordinates of the factors which remedy the two equations, i.e. the intersects between the two.
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Verified answer
First, remember that x = rcos(θ) and y = rsin(θ)!!!!!!!
x = 4sin(θ)cos(θ)
y = 4sin²(θ)
For polar functions, to find dy/dx, you do this:
dy/dx = dy/dθ / dx/dθ
dy/dθ = 8cos(θ)sin(θ)
dx/dθ = 4cos(2θ)
dy/dθ / dx/dθ = 8cos(θ)sin(θ)/4cos(2θ)
= 2cos(θ)sin(θ)/cos(2θ)
Now, just plug in θ = π/6:
8cos(π/6)sin(π/6)/4cos(π/3)
= √3
√3 is the same as 3^(1/2), so the answer is 'd'
The question is stated more than a little ambiguously, but I presume you mean:
(i) the polar curve is given by : r = f(Θ) = 4 sin Θ.
[Without any mention of ' r ,' it's NOT a polar equation! It simply defines a function f(Θ) of Θ --- no big deal, but that's NOTHING to do with a polar equation. I'm afraid that the previous two responders just didn't recognize that.]
(ii) I also presume that the slope of the tangent is required with respect to the line Θ = 0, and NOT with respect to the polar curve itself.
In that case, the answer is d.) 3^(1/2). Here's why:
Let the tangent make an angle ' fi ' with respect to the radial vector. Then standard results (easily seen from a simple sketch) are:
(a) tan fi = r dΘ / dr ; and
(b) the angle the tangent makes with the line Θ = 0 is fi + Θ.
Now for the calculation:
If r = 4 sin Θ, then dr / dΘ = 4 cos Θ, therefore
tan fi = (4 sin Θ) / (4 cos Θ) = tan Θ (!)
Therefore fi = Θ = π/6. Thus the angle the tangent makes with the line Θ = 0 is fi + Θ = π/6 + π/6 = π/3. And tan π/3 = 3^(1/2), of course.
Hence the answer is d.) 3^(1/2)
Live long and prosper.
You already calculated your spinoff. Now, plug on your factor (0,0) and prepare that it yields a million/2, it is the slope of your tangent. Now, set the tangent equivalent on your function, i.e. x/2 = (2x)/... remedy this for x. Your ideas are then the x coordinates of the factors which remedy the two equations, i.e. the intersects between the two.
f'(Θ) = 4cosΘ
f'(π/6) = 4cos(π/6) = 2√3
f'(Θ)=4cosΘ
f'(π/6)=4cos(π/6)=4*3^(1/2)*1/2=2*3^(1/2)