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1.2

x=2+3y+1,x=2+3y+1, or y=−1+3x2.y=−1+3x2. This equation describes a portion of a rectangular hyperbola centered at (2,−1).(2,−1).

1.3

One possibility is x(t)=t,y(t)=t2+2t.x(t)=t,y(t)=t2+2t. Another possibility is x(t)=2t3,y(t)=(2t3)2+2(2t3)=4t28t+3.x(t)=2t3,y(t)=(2t3)2+2(2t3)=4t28t+3.

There are, in fact, an infinite number of possibilities.

1.4

x(t)=2t4x(t)=2t4 and y(t)=6t26,y(t)=6t26, so dydx=6t262t4=3t23t2.dydx=6t262t4=3t23t2.
This expression is undefined when t=2t=2 and equal to zero when t=±1.t=±1.

1.5

The equation of the tangent line is y=24x+100.y=24x+100.

1.6

d2ydx2=3t212t+32(t2)3.d2ydx2=3t212t+32(t2)3. Critical points (5,4),(−3,−4),and(−4,4).(5,4),(−3,−4),and(−4,4).

1.7

A=3πA=3π (Note that the integral formula actually yields a negative answer. This is due to the fact that x(t)x(t) is a decreasing function over the interval [0,2π];[0,2π]; that is, the curve is traced from right to left.)

1.8

s = 2 ( 10 3 / 2 2 3 / 2 ) 57.589 s = 2 ( 10 3 / 2 2 3 / 2 ) 57.589

1.9

A = π ( 494 13 + 128 ) 1215 A = π ( 494 13 + 128 ) 1215

1.10

(82,5π4)(82,5π4) and (−2,23)(−2,23)

1.12



The name of this shape is a cardioid, which we will study further later in this section.

1.13

y=x2,y=x2, which is the equation of a parabola opening upward.

1.14

Symmetric with respect to the polar axis.

1.15

A = 3 π / 2 A = 3 π / 2

1.16

A = 4 π 3 + 2 3 A = 4 π 3 + 2 3

1.17

s = 3 π s = 3 π

1.18

x=2(y+3)22x=2(y+3)22

1.19

(x+1)216+(y2)29=1(x+1)216+(y2)29=1

1.20

(y+2)29(x1)24=1.(y+2)29(x1)24=1. This is a vertical hyperbola. Asymptotes y=−2±32(x1).y=−2±32(x1).

1.21

e = c a = 74 7 1.229 e = c a = 74 7 1.229

1.22

Here e=0.8e=0.8 and p=5.p=5. This conic section is an ellipse.

1.23

The conic is a hyperbola and the angle of rotation of the axes is θ=22.5°.θ=22.5°.

Section 1.1 Exercises

1.



orientation: bottom to top

3.



orientation: left to right

5.

y=x24+1y=x24+1

7.


9.


11.


13.


15.



Asymptotes are y=xy=x and y=xy=x

17.


19.


21.

y=x+12y=x+12; domain: x[–1,).x[–1,).

23.

x216+y29=1;x216+y29=1; domain x[−4,4].x[−4,4].

25.

y=3x+2;y=3x+2; domain: all real numbers.

27.

(x1)2+(y3)2=1;(x1)2+(y3)2=1; domain: x[0,2].x[0,2].

29.

y=x21;y=x21; domain: x(-∞,-1].x(-∞,-1].

31.

y2=1x2;y2=1x2; domain: x[-1,1].x[-1,1].

33.

y=lnx;y=lnx; domain: x[1,).x[1,).

35.

y=lnx;y=lnx; domain: x(0,).x(0,).

37.

x2+y2=4;x2+y2=4; domain: x[−2,2].x[−2,2].

39.

line

41.

parabola

43.

circle

45.

ellipse

47.

hyperbola

51.

The equations represent a cycloid.

53.


55.

22,092 meters at approximately 51 seconds.

57.


59.


61.


Section 1.2 Exercises

63.

0

65.

−3 5 −3 5

67.

Slope=0;Slope=0; y=8.y=8.

69.

Slope is undefined; x=2.x=2.

71.

tan t = -2(45,−85), (45,−85)tan t = -2(45,−85), (45,−85), -45,85-45,85.

73.

No points possible; undefined expression.

75.

y = ( 4 e ) x + 5 y = ( 4 e ) x + 5

77.

y = –2 x + 3 y = –2 x + 3

79.

π 4 , 5 π 4 , 3 π 4 , 7 π 4 π 4 , 5 π 4 , 3 π 4 , 7 π 4

81.

d y d x = tan ( t ) d y d x = tan ( t )

83.

dydx=34dydx=34 and d2ydx2=0,d2ydx2=0, so the curve is neither concave up nor concave down at t=3.t=3. Therefore the graph is linear and has a constant slope but no concavity.

85.

dydx=4,d2ydx2=−63;dydx=4,d2ydx2=−63; the curve is concave down at θ=π6.θ=π6.

87.

No horizontal tangents. Vertical tangents at (1,0),(−1,0).(1,0),(−1,0).

89.

sec 3 ( π t ) sec 3 ( π t )

91.

Horizontal (0,−9);(0,−9); vertical (±2,−6).(±2,−6).

93.

1

95.

0

97.

4

99.

Concave up on t>0.t>0.

101.

e π 2 1 2 e π 2 1 2

103.

3 π 2 3 π 2

105.

6 π a 2 6 π a 2

107.

2 π a b 2 π a b

109.

1 3 ( 2 2 1 ) 1 3 ( 2 2 1 )

111.

7.075 7.075

113.

6 a 6 a

115.

6 2 6 2

119.

2 π ( 247 13 + 64 ) 1215 2 π ( 247 13 + 64 ) 1215

121.

59.101

123.

8 π 3 ( 17 17 1 ) 8 π 3 ( 17 17 1 )

Section 1.3 Exercises

125.


127.


129.


131.


133.

B ( 3 , π 3 ) B ( −3 , 2 π 3 ) B ( 3 , π 3 ) B ( −3 , 2 π 3 )

135.

D ( 5 , 7 π 6 ) D ( −5 , π 6 ) D ( 5 , 7 π 6 ) D ( −5 , π 6 )

137.

( 5 ,   5 . 356 )   ( 5 ,   2 . 214 ) ( 5 ,   5 . 356 )   ( 5 ,   2 . 214 )

139.

( 10 ,   2 . 214 ) ( 10 ,   5 . 356 ) ( 10 ,   2 . 214 ) ( 10 ,   5 . 356 )

141.

( 2 3 , −5.759 ) ( −2 3 , 2.618 ) ( 2 3 , −5.759 ) ( −2 3 , 2.618 )

143.

( 3 , −1 ) ( 3 , −1 )

145.

( 3 2 , −1 2 ) ( 3 2 , −1 2 )

147.

( 0 , 0 ) ( 0 , 0 )

149.

Symmetry with respect to the x-axis, y-axis, and origin.

151.

Symmetric with respect to x-axis only.

153.

Symmetry with respect to x-axis only.

155.

Line y=xy=x

157.

y = 1 y = 1

159.

Hyperbola; polar form r2cos(2θ)=16r2cos(2θ)=16 or r2=16sec(2θ).r2=16sec(2θ).

161.

r=23cosθsinθr=23cosθsinθ

163.

x2+y2=4yx2+y2=4y

165.

xtanx2+y2=yxtanx2+y2=y

167.



y-axis symmetry

169.



y-axis symmetry

171.



x- and y-axis symmetry and symmetry about the pole

173.



x-axis symmetry

175.



x- and y-axis symmetry and symmetry about the pole

177.



no symmetry

179.



a line

181.


183.


185.


187.

Answers vary. One possibility is the spiral lines become closer together and the total number of spirals increases.

Section 1.4 Exercises

189.

9 2 0 π sin 2 θ d θ 9 2 0 π sin 2 θ d θ

191.

32 0 π / 2 sin 2 ( 2 θ ) d θ 32 0 π / 2 sin 2 ( 2 θ ) d θ

193.

1 2 π 2 π ( 1 sin θ ) 2 d θ 1 2 π 2 π ( 1 sin θ ) 2 d θ

195.

sin −1 ( 2 / 3 ) π / 2 ( 2 3 sin θ ) 2 d θ sin −1 ( 2 / 3 ) π / 2 ( 2 3 sin θ ) 2 d θ

197.

π / 3 π ( 1 2 cos θ ) 2 d θ 0 π / 3 ( 1 2 cos θ ) 2 d θ π / 3 π ( 1 2 cos θ ) 2 d θ 0 π / 3 ( 1 2 cos θ ) 2 d θ

199.

4 0 π / 3 d θ + 16 π / 3 π / 2 ( cos 2 θ ) d θ 4 0 π / 3 d θ + 16 π / 3 π / 2 ( cos 2 θ ) d θ

201.

9 π 9 π

203.

9 π 4 9 π 4

205.

9 π 8 9 π 8

207.

18 π 27 3 2 18 π 27 3 2

209.

4 3 ( 4 π 3 3 ) 4 3 ( 4 π 3 3 )

211.

3 2 ( 4 π 3 3 ) 3 2 ( 4 π 3 3 )

213.

2 π 4 2 π 4

215.

0 2 π ( 1 + sin θ ) 2 + cos 2 θ d θ 0 2 π ( 1 + sin θ ) 2 + cos 2 θ d θ

217.

2 0 1 e θ d θ 2 0 1 e θ d θ

219.

10 3 ( e 6 1 ) 10 3 ( e 6 1 )

221.

32

223.

6.238

225.

2

227.

4.39

229.

A = π ( 2 2 ) 2 = π 2 and 1 2 0 π ( 1 + 2 sin θ cos θ ) d θ = π 2 A = π ( 2 2 ) 2 = π 2 and 1 2 0 π ( 1 + 2 sin θ cos θ ) d θ = π 2

231.

C = 2 π ( 3 2 ) = 3 π and 0 π 3 d θ = 3 π C = 2 π ( 3 2 ) = 3 π and 0 π 3 d θ = 3 π

233.

C = 2 π ( 5 ) = 10 π and 0 π 10 d θ = 10 π C = 2 π ( 5 ) = 10 π and 0 π 10 d θ = 10 π

235.

d y d x = f ( θ ) sin θ + f ( θ ) cos θ f ( θ ) cos θ f ( θ ) sin θ d y d x = f ( θ ) sin θ + f ( θ ) cos θ f ( θ ) cos θ f ( θ ) sin θ

237.

The slope is 13.13.

239.

The slope is 0.

241.

At (4,0),(4,0), the slope is undefined. At (−4,π2),(−4,π2), the slope is 0.

243.

The slope is undefined at θ=π4.θ=π4.

245.

Slope = −1.

247.

Slope is −2π.−2π.

249.

Calculator answer: −0.836.

251.

Horizontal tangent at (±2,π6),(±2,π6), (±2,π6).(±2,π6).

253.

Horizontal tangents at π2,7π6,11π6.π2,7π6,11π6. Vertical tangents at π6,5π6π6,5π6 and also at the pole (0,0).(0,0).

Section 1.5 Exercises

255.

y 2 = 16 x y 2 = 16 x

257.

x 2 = 2 y x 2 = 2 y

259.

x 2 = −4 ( y 3 ) x 2 = −4 ( y 3 )

261.

( x + 3 ) 2 = 8 ( y 3 ) ( x + 3 ) 2 = 8 ( y 3 )

263.

x 2 16 + y 2 12 = 1 x 2 16 + y 2 12 = 1

265.

x 2 13 + y 2 4 = 1 x 2 13 + y 2 4 = 1

267.

( y 1 ) 2 16 + ( x + 3 ) 2 12 = 1 ( y 1 ) 2 16 + ( x + 3 ) 2 12 = 1

269.

x 2 16 + y 2 12 = 1 x 2 16 + y 2 12 = 1

271.

x 2 25 y 2 11 = 1 x 2 25 y 2 11 = 1

273.

x 2 7 y 2 9 = 1 x 2 7 y 2 9 = 1

275.

( y + 2 ) 2 4 ( x + 2 ) 2 32 = 1 ( y + 2 ) 2 4 ( x + 2 ) 2 32 = 1

277.

x 2 4 y 2 32 = 1 x 2 4 y 2 32 = 1

279.

e=1,e=1, parabola

281.

e=12,e=12, ellipse

283.

e=3,e=3, hyperbola

285.

r = 4 5 + cos θ r = 4 5 + cos θ

287.

r = 4 1 + 2 sin θ r = 4 1 + 2 sin θ

289.


291.


293.


295.


297.


299.


301.


303.


305.


307.

Hyperbola

309.

Ellipse

311.

Ellipse

313.

At the point 2.25 feet above the vertex.

315.

0.5625 feet

317.

Length is 96 feet and height is approximately 26.53 feet.

319.

r = 2.616 1 + 0.995 cos θ r = 2.616 1 + 0.995 cos θ

321.

r = 5.192 1 + 0.0484 cos θ r = 5.192 1 + 0.0484 cos θ

Review Exercises

323.

True.

325.

False. Imagine y=t+1,y=t+1, x=t+1.x=t+1.

327.



y=1x3y=1x3

329.



x216+(y1)2=1x216+(y1)2=1

331.



Symmetric about polar axis

333.

r 2 = 4 sin 2 θ cos 2 θ r 2 = 4 sin 2 θ cos 2 θ

335.



y=322+15(x+322)y=322+15(x+322)

337.

e 2 2 e 2 2

339.

9 10 9 10

341.

( y + 5 ) 2 = −8 x + 32 ( y + 5 ) 2 = −8 x + 32

343.

( y + 1 ) 2 16 ( x + 2 ) 2 9 = 1 ( y + 1 ) 2 16 ( x + 2 ) 2 9 = 1

345.

e=23,e=23, ellipse

347.

y219.032+x219.632=1,y219.032+x219.632=1, e=0.2447e=0.2447

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