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Solução_Calculo_Stewart_6e

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F.<br />

426 ¤ CHAPTER 10 PARAMETRIC EQUATIONS AND POLAR COORDINATES TX.10<br />

43. r 2 =9sin2θ<br />

45. r =2cos 3<br />

2 θ<br />

47. r =1+2cos2θ<br />

49. For θ =0, π,and2π, r has its minimum value of about 0.5. Forθ = π and 3π , r attains its maximum value of 2.<br />

2 2<br />

We see that the graph has a similar shape for 0 ≤ θ ≤ π and π ≤ θ ≤ 2π.<br />

51. x =(r)cosθ =(4+2secθ)cosθ =4cosθ +2.Now,r →∞ ⇒<br />

(4 + 2 sec θ) →∞ ⇒ θ → <br />

π −<br />

or θ → <br />

3π +<br />

[since we need only<br />

2<br />

2<br />

consider 0 ≤ θ

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