U A E University, College of Science Department of Mathematical Sciences Final Exam Spring 2007 MATH 1120 CALCULUS II FOR ENGINEERS Student’s Name Student’s I.D. Section # Check The Name of Your Instructor John Abraham - Section 51 Nora Merabet - Section 01 John Abraham - Section 52 Nora Merabet - Section 02 Sherif Moussa - Section 53 Naim Markos - Section 03 Nabila Azam - Section 54 Allowed time is 2 hours. You can use the back of the sheets. NO BOOKS. NO NOTES. NO PROGRAMING CALCULATORS Section I Problem # Points Section II Problem # 1-10 Points Total Points Section I: Multiple choice problems [50 Points, 5 each] (No Partial Credits for this Section) r r r r r r 1. The projection of the vector u = i + 3 j on the vector v = 4i + 2k , is r r i+ j A) r r B) 2i + j r r r C) 2i − j r D) i + 2 j 2. A unit vector perpendicular to the plane that contains the points P (1, − 1, 0) , Q(2, 1, − 1) and R (−1, 1, 2) is r r i j + 2 2 A) r r i j B) − 2 2 C) 3. The order of integration of the integral 5 x2 f ( x, y ) dydx 25 5 f ( x, y ) dydx A) ∫0 ∫0 C) ∫0 ∫ x B) 5 x2 ∫0 ∫0 D) 5 y2 ∫0 ∫0 25 5 r D) 1 r r r (i + j + k ) 2 f ( x, y ) dxdy can be changed into f ( x, y ) dydx ∫0 ∫ 4. The directional derivative of the function r r r i k + 2 2 x f ( x, y ) dydx f ( x, y ) = y 2 e 4 x at the point (0, − 2) in the direction of u , such that u is parallel and in the same direction as 3,−1 is A) 5 2 10 5. The maximum rate of change of A) 1 B) B) 0 52 10 C) 52 5 D) 52 3 10 f ( x, y ) = x cos(3 y ) at the point (−2, π ) is C) 6 D) 3 2-10 6. The volume of the solid bounded by the surfaces z = 1 − y , and x = 2 is A) 2 7. B) 3 2 C) 1 2 z = 0, y = 0 , x =1 D) 3 ( ) 3 2 2 2 The form of the equation e x e y e z x 2 + y 2 + z 2 z = 1 in spherical coordinates is 3 ρ A) ρ e cos φ = 1 2 6 ρ B) ρ e cos φ sin θ = 1 7 ρ C) ρ e cos φ = 1 6 ρ D) ρ e cos φ cos θ = 1 2 8. The function f ( x, y ) = A) no critical point C) only two critical points 2 2 x 3 − 2 y 2 − 2 y 4 + 3x 2 y has B) only one critical point D) only three critical points r r v r = x i + y j be the position vector in 2 dimensions. For the function 1 f ( x, y ) = 9 − ( x 2 + y 2 ) the gradient of f ( x, y ) is 4 1v 1v v v A) − r B) − 2 r C) − r D) − r 2 4 9. Let r 10. the curl of the vector field F = xy, yz, x 2 is A) − x, y, − x B) − 2 y, − 2 x, − x C) − y, − 2 x, − x D) − x, − 2 x, − y 3-10 Section II: Multiple-Step problems [150 Points, 15 each] 1. Find the unit vector in 2 dimensional-space that makes angle 60 with the positive x-axis. 2. Suppose that a box is being towed up an inclined, frictionless, plane as shown in r figure. Find the force F needed to make the component of the force parallel to the inclined plane equal to 2.5 lb. F 30 15 4-10 3. Determine if the lines ⎧x = 4 + t ⎪ and ⎨y = 2 ⎪ z = 3 + 2t ⎩ ⎧ x = 2 + 2s ⎪ ⎨ y = 2s ⎪ z = −1 + 4s ⎩ are parallel, skew or intersect. If they intersect, then find the point of intersection. 5-10 4. The gas law for a fixed mass m of an ideal gas at absolute temperature T , pressure P , and volume V is PV = mRT , where R is the gas constant. Show that 5. ∂P ∂V ∂T = −1 ∂V ∂T ∂P Suppose that the temperature of a metal plate is given by T ( x, y ) = 4 x 2 − 4 xy + y 2 , for points (x, y) on the circular plate defined by x 2 + y 2 = 25 . Find the maximum and minimum temperatures on the plate. 6-10 6. Lamina bounded by y = x ( x > 0 ), y = 4 and 2 x = 0 , where the density . ρ ( x, y ) = distance from y - axis i) Sketch the region ii) Find the mass of the lamina iii) Find, x , the x-coordinate of the center of mass. 7-10 7. Use polar coordinates to evaluate the double integral ∫∫ y dA where R is the R region r = 2 − 2 cosθ 8. Sketch the box with dimensions 2, 4, 6 units, and then Use the triple integral to find its volume. 8-10 r 9. Compute the work done by the force F = 2 x, 2 y 2 along the curve C defined by C: is the quarter-circle from (4, 0) to (0, 4). 10 . Put "T" for the correct statement or relation and "F" for the wrong ones. r r r r a) For any two vectors we always have a + b = a + b b) Any two lines can lie in a plane. r v r c) For a particle moving in the circle r = cos t i + sin t j , the velocity is always perpendicular to the position vector. d) In 2-dimensions the polar coordinate θ = 30 represents a point. r r r e) The curve r = cos 3t i + sin 3t j can't represent circle f) Using the cylindrical coordinates, the equation ( x − 2) + y = 4 will take the form r = 2 cosθ . 2 r r g) A vector field F is conservative if ∇ × F = 0 . r r h) For the position vector r , div r =0 9-10 2 BONUS (10 Points) A rectangular box is to be inscribed in the cone z = 9 − x + y , z ≥ 0 . Find the dimensions for the box that maximize its volume. 2 10-10 2
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