Convert the equation r cos theta = sin (2 theta) to Cartesian coordinates. Describe the resulting curves. Choose the correct equations below. A. x^2+ y^2 =1^2 and x = 0 B. (x - 1)^2 (y - 1)^ and x = 0 C. (x - 1)^2 + y^2 and x = 0 D. x^2 (y - 1)^2 = 1^2 and x = 0

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Answer:

Correct option (D) x = 0 or x² + (y - 1)² = 1².

Step-by-step explanation:

The trigonometric equation is: [tex]r\ Cos\ \theta=Sin\ 2\theta[/tex]

The expansion of [tex]Sin\ 2\theta[/tex] is:

[tex]Sin\ 2\theta=2\ Sin\ \theta \ Cos\ \theta[/tex]

Then the equation is:

[tex]r\ Cos\ \theta=Sin\ 2\theta\\r\ Cos\ \theta=2\ Sin\ \theta \ Cos\ \theta[/tex]

Now either [tex]Cos\ \theta=0[/tex] or [tex]r=2Sin\ \theta[/tex]

In Cartesian form:  

[tex]x=Cos\ \theta\\y=Sin\ \theta[/tex]

Then either

x = 0

Or,

[tex]\sqrt{x^{2}+y^{2}}=\frac{2y}{\sqrt{x^{2}+y^{2}}}\\x^{2}+y^{2}-2y=0\\x^{2}+y^{2}-2y+1=1\\x^{2}+(y-1)^{2}=1[/tex]

Thus, the resulting curve is: x = 0 or x² + (y - 1)² = 1².