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Find the curvature of the curve r(t) =2ti+6tj+9k\mathbf { r } ( t ) = 2 t \mathbf { i } + 6 t \mathbf { j } + 9 \mathbf { k } .


A) 1
B) 2102 \sqrt { 10 }
C) 11
D) 0

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Find the length of the curve r(t) =2titj+tk\mathbf { r } ( t ) = - 2 t \mathbf { i } - t \mathbf { j } + t \mathbf { k } 2t1.- 2 \leq t \leq 1 .


A) 363 \sqrt { 6 }
B) 6\sqrt { 6 }
C) 262 \sqrt { 6 }
D) 666 \sqrt { 6 }

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Find the unit tangent vector T(t) T ( t ) . r(t) =2sint,4t,2cost\mathbf { r } ( t ) = \langle 2 \sin t , 4 t , 2 \cos t \rangle


A) cost25,25,sint25\left\langle\frac { \cos t } { 2 \sqrt { 5 } } , \frac { 2 } { \sqrt { 5 } } , - \frac { \sin t } { 2 \sqrt { 5 } } \right\rangle
B) 3cost,6,3sint\langle3 \cos t , 6 , - 3 \sin t \rangle
C) cost5,25,sint5\left\langle\frac { \cos t } { \sqrt { 5 } } , \frac { 2 } { \sqrt { 5 } } , - \frac { \sin t } { \sqrt { 5 } } \right\rangle
D) 35cost,6,35sint\langle3 \sqrt { 5 } \cos t , 6 , - 3 \sqrt { 5 } \sin t \rangle
E) cost25,425,3sint25\left\langle- \frac { \cos t } { 2 \sqrt { 5 } } , \frac { 4 } { 2 \sqrt { 5 } } , \frac { 3 \sin t } { 2 \sqrt { 5 } } \right\rangle

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Find the acceleration of a particle with the given position function. r(t) =9sinti+10tj8costk\mathbf { r } ( t ) = 9 \sin t \mathbf { i } + 10 t \mathbf { j } - 8 \cos t \mathbf { k }


A) a(t) =9sinti9costj\mathbf { a } ( t ) = - 9 \sin t \mathbf { i } - 9 \cos t \mathbf { j }
B) a(t) =9sinti+9costj\mathbf { a } ( t ) = - 9 \sin t \mathbf { i } + 9 \cos t \mathbf { j }
C) a(t) =9sinti+10costk\mathbf { a } ( t ) = - 9 \sin t \mathbf { i } + 10 \cos t \mathbf { k }
D) a(t) =9sinti+8costk\mathbf { a } ( t ) = - 9 \sin t \mathbf { i } + 8 \cos t \mathbf { k }
E) a(t) =9sinti10tk\mathbf { a } ( t ) = 9 \sin t \mathbf { i } - 10 t \mathbf { k }

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Two points A and B are located 100 ft apart on a straight line. A particle moves from A toward B with an initial velocity of 9 ft/sec and an acceleration of 12\frac { 1 } { 2 } ft/sec2\mathrm { ft } / \mathrm { sec } ^ { 2 } . Simultaneously, a particle moves from B toward A with an initial velocity of 2 ft/sec and an acceleration of 34\frac { 3 } { 4 } ft/sec2\mathrm { ft } / \mathrm { sec } ^ { 2 } . When will the two particles collide? At what distance from A will the collision take place?

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Find the point(s) on the graph of y=e11x2y = e ^ { - 11 x ^ { 2 } } at which the curvature is zero.

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Find r(t)\mathbf { r } ^ { \prime } ( t ) and r(t)\mathbf { r } ^ { \prime \prime } ( t ) for r(t)=tcos3tsin3t,tsin4t+cos4t\mathbf { r } ( t ) = \langle t \cos 3 t - \sin 3 t , t \sin 4 t + \cos 4 t \rangle

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\[\begin{array} { l }
\mathbf { r } ^ {...

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Find the domain of the vector function r(t) =8ti+1t4j\mathbf { r } ( t ) = 8 t \mathbf { i } + \frac { 1 } { t - 4 } \mathbf { j } .


A) (,4) (4,) ( - \infty , - 4 ) \cup ( - 4 , \infty )
B) (,8) (8,) ( - \infty , 8 ) \cup ( 8 , \infty )
C) (,8) (8,) ( - \infty , - 8 ) \cup ( - 8 , \infty )
D) (,4) (4,) ( - \infty , 4 ) \cup ( 4 , \infty )

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Find the limit limte4t,1t,7t2t2+1\lim _ { t \rightarrow \infty } \left\langle e ^ { - 4 t } , \frac { 1 } { t } , \frac { 7 t ^ { 2 } } { t ^ { 2 } + 1 } \right\rangle .

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For the curve given by r(t) =(4sint,5t,4cost) \mathbf { r } ( t ) = (4 \sin t , 5 t , 4 \mathrm { cos } t ) , find the unit normal vector. a(t) =2k,v(0) =10i9j\mathbf { a } ( t ) = 2 \mathbf { k } , \mathbf { v } ( 0 ) = 10 \mathbf { i } - 9 \mathbf { j }


A) (2sint,5,2cost) ( 2 \sin t , 5 , - 2 \cos t)
B) (2sint,0,2cost) (- 2 \sin t , 0 , - 2 \cos t )
C) (sint29,0,cost29) \left( - \frac { \sin t } { \sqrt { 29 } } , 0 , - \frac { \cos t } { \sqrt { 29 } } \right)
D) (29sint,0,29cost) ( \sqrt { 29 } \sin t , 0 , - \sqrt { 29 } \mathrm { cost } )
E) None of these

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Find the scalar tangential and normal components of acceleration of a particle with position vector r(t) =3sinti+3costj+5tk\mathbf { r } ( t ) = 3 \sin t \mathbf { i } + 3 \cos t \mathbf { j } + 5 t \mathbf { k }


A) aT=0a _ { \mathbf { T } } = 0 aN=3a _ { \mathrm { N } } = 3
B) aT=5a _ { \mathbf { T } } = 5 aN=3a _ { \mathrm { N } } = 3
C) aT=0a _ { \mathbf { T } } = 0 aN=326a _ { \mathrm { N } } = 3 \sqrt { 26 }
D) aT=5a _ { \mathbf { T } } = 5 aN=326a _ { \mathrm { N } } = 3 \sqrt { 26 }

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The curvature of the curve given by the vector function rr is k(t) =r(t) ×r(t) r(t) 3k ( t ) = \frac { \left| \mathbf { r } ^ { \prime } ( t ) \times \mathbf { r } ^ { \prime \prime } ( t ) \right| } { \left| \mathbf { r } ^ { \prime } ( t ) \right| ^ { 3 } } Use the formula to find the curvature of r(t) =13t,et,et\mathbf { r } ( t ) = \left\langle \sqrt { 13 } t , e ^ { t } , e ^ { - t } \right\rangle at the point (0,1,1) ( 0,1,1 ) .


A) 15\sqrt { 15 }
B) 215\frac { \sqrt { 2 } } { 15 }
C) 15215 \sqrt { 2 }
D) 152\frac { 15 } { \sqrt { 2 } }
E) 1515\frac { \sqrt { 15 } } { 15 }

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Let r(t) =6t,(et2) t,ln(t+1) \mathbf { r } ( t ) = \left\langle \sqrt { 6 - t } , \frac { \left( e ^ { t } - 2 \right) } { t } , \ln ( t + 1 ) \right\rangle . Find the domain of rr .


A) (2,6]( - 2,6 ]
B) (2,0) (0,6]( - 2,0 ) \cup ( 0,6 ]
C) (6,]( 6 , \infty ]
D) (,2) ( - \infty , - 2 )
E) [6,0) (0,2) [ 6,0 ) \cup ( 0,2 )

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Find r(t) \mathbf { r } ( t ) satisfying the conditions for rt(t) =9e9ti+9etj+etk\mathbf { r } ^ { t } ( t ) = 9 e ^ { 9 t } \mathbf { i } + 9 e ^ { - t } \mathbf { j } + e ^ { t } \mathbf { k } r(0) =ij+9k\mathbf { r } ( 0 ) = \mathbf { i } - \mathbf { j } + 9 \mathbf { k }


A) (e9t+1) i(9et+1) j+(et+9) k\left( e ^ { 9 t } + 1 \right) \mathbf { i } - \left( 9 e ^ { - t } + 1 \right) \mathbf { j } + \left( e ^ { t } + 9 \right) \mathbf { k }
B) 9e9ti(9et+8) j+(et+8) k9 e ^ { 9 t } \mathbf { i } - \left( 9 e ^ { - t } + 8 \right) \mathbf { j } + \left( e ^ { t } + 8 \right) \mathbf { k }
C) e9ti(9et8) j+(et+8) ke ^ { 9 t } \mathbf { i } - \left( 9 e ^ { - t } - 8 \right) \mathbf { j } + \left( e ^ { t } + 8 \right) \mathbf { k }
D) (9e9t+1) i(9et1) j+(et+9) k\left( 9 e ^ { 9 t } + 1 \right) \mathbf { i } - \left( 9 e ^ { - t } - 1 \right) \mathbf { j } + \left( e ^ { t } + 9 \right) \mathbf { k }

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Find r(t)\mathbf { r } ^ { \prime } ( t ) and r(t)\mathbf { r } ^ { \prime \prime } ( t ) for r(t)=5ti+4t2j+5t3k\mathbf { r } ( t ) = 5 t \mathbf { i } + 4 t ^ { 2 } \mathbf { j } + 5 t ^ { 3 } \mathbf { k }

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\[\begin{array} { l }
\mathbf { r } ^ {...

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The helix r1(t) =8costi+sintj+tk\mathbf { r } _ { 1 } ( t ) = 8 \cos t \mathbf { i } + \sin t \mathbf { j } + t \mathbf { k } intersects the curve r2(t) =(8+t) i+10t2j+9t3k\mathbf { r } _ { 2 } ( t ) = ( 8 + t ) \mathbf { i } + 10 t ^ { 2 } \mathbf { j } + 9 t ^ { 3 } \mathbf { k } at the point (8,0,0) ( 8,0,0 ) . Find the angle of intersection.


A) π3\frac { \pi } { 3 }
B) π4\frac { \pi } { 4 }
C) π2\frac { \pi } { 2 }
D) 00
E) None of these

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A particle moves with position function r(t)=42ti+e4tj+e4tk\mathbf { r } ( t ) = 4 \sqrt { 2 } t \mathbf { i } + e ^ { 4 t } \mathbf { j } + e ^ { - 4 t } \mathbf { k } . Find the acceleration of the particle.

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Find a vector function that represents the curve of intersection of the two surfaces: The circular cylinder x2+y2=9x ^ { 2 } + y ^ { 2 } = 9 and the parabolic cylinder z=xyz = x y .


A) r(t) =costi+sintj9cos2tk\mathbf { r } ( t ) = \cos t \mathbf { i } + \sin t \mathbf { j } - 9 \cos 2 t \mathbf { k }
B) r(t) =3cos(t) i+3sin(t) j+9sin(t) cos(t) k\mathbf { r } ( t ) = 3 \cos ( t ) \mathbf { i } + 3 \sin ( t ) \mathbf { j } + 9 \sin ( t ) \cos ( t ) \mathbf { k }
C) r(t) =3cos(t) i+3sin(t) jsin(t) cos(t) k\mathbf { r } ( t ) = 3 \cos ( t ) \mathbf { i } + 3 \sin ( t ) \mathbf { j } - \sin ( t ) \cos ( t ) \mathbf { k }
D) r(t) =cos(t) i+sin(t) j+9sin(t) cos(t) k\mathbf { r } ( t ) = \cos ( t ) \mathbf { i } + \sin ( t ) \mathbf { j } + 9 \sin ( t ) \cos ( t ) \mathbf { k }
E) r(t) =9costi+9tj+9cos2tk\mathbf { r } ( t ) = 9 \cos t \mathbf { i } + 9 t \mathbf { j } + 9 \cos ^ { 2 } t \mathbf { k }

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Find the point of intersection of the tangent lines to the curve r(t)=(sinπt,5sinπt,cosπt)\mathbf { r } ( t ) = ( \sin \pi t , 5 \sin \pi t , \cos \pi t ) , at the points where t=0t = 0 and t=0.5t = 0.5 .

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Sketch the curve of the vector function r(t)=t2,t3,t\mathbf { r } ( t ) = \left\langle t ^ { 2 } , t ^ { 3 } , t \right\rangle t0t \geq 0 and indicate the orientation of the curve.

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