I)\ The angle between

(:2,1,-1:)

and

(:2,1,5:)

is:\ (A) obtuse\ (B) acute\ (C) a right angle\ II)

,(:3,4,1:)\\\\times (:1,2,3:)

is equal to:\ (A)

(:10,-8,2:)

\ (B)

(:-10,8,-2:)

\ (C)

(:10,-8,-2:)

\ III)\

f(x,y)=(1)/(\\\\sqrt(x^(2)+y^(2)-1))

is continuous at any point in

R^(2)

that is:\ (A) outside the circle

x^(2)+y^(2)=1

\ (B) inside the circle

x^(2)+y^(2)=1

\ IV)\ Which of these points is NOT on the line

r(t)=(:6+5t,4+3t,2+t:)

?\ (A)

(6,4,2)

\ (B)

(5,3,1)

\ (C)

(11,7,3)

\ V) For the surface

2x^(2)-3y+4z^(2)=4

, the trace in the

xz

plane is:\ (A) an ellipse\ (B) a parabola\ (C) a hyperbola\ VI) Which best describes the space curve

r(t)=(:2sin(\\\\pi t),5,2cos(\\\\pi t):)

?\ (A) a spiral\ (B) a line segment\ (C) a circle