General Instructions: (i) All questions are compulsory. (ii) This question paper contains 29 questions. (iii) Questions 1- 4 in Section A are very short-answer type questions carrying 1 mark each. (iv) Questions 5-12 in Section B are short-answer type questions carrying 2 marks each. (v) Questions 13-23 in Section C are long-answer I type questions carrying 4 marks each. (vi) Questions 24-29 in Section D are long-answer II type questions carrying 6 marks each.
Question 1
Find the magnitude of each of two vectors and , having the same magnitude such that the angle between them is 60° and their scalar product is . VIEW SOLUTION
If a * b denotes the larger of 'a' and 'b' and if = (a * b) + 3, then write the value of , where * and are binary operations. VIEW SOLUTION
Question 4
If the matrix is skew symmetric, find the values of 'a' and 'b'. VIEW SOLUTION
Question 5
A black and a red die are rolled together. Find the conditional probability of obtaining the sum 8, given that the red die resulted in a number less than 4. VIEW SOLUTION
Question 6
If θ is the angle between two vectors , find sin θ. VIEW SOLUTION
Question 7
Find the differential equation representing the family of curves y = aebx+5, where a and b are arbitrary constants. VIEW SOLUTION
The total cost C(x) associated with the production of x units of an item is given by C(x) = 0.005x3 – 0.02x2 + 30x + 5000. Find the marginal cost when 3 units are produced, where by marginal cost we mean the instantaneous rate of change of total cost at any level of output. VIEW SOLUTION
Two numbers are selected at random (without replacement) from the first five positive integers. Let X denote the larger of the two numbers obtained. Find the mean and variance of X. VIEW SOLUTION
Question 14
An open tank with a square base and vertical sides is to be constructed from a metal sheet so as to hold a given quantity of water. Show that the cost of material will be least when depth of the tank is half of its width. If the cost is to be borne by nearby settled lower income families, for whom water will be provided, what kind of value is hidden in this question? VIEW SOLUTION
Question 15
Find the equations of the tangent and the normal, to the curve 16x2 + 9y2= 145 at the point (x1, y1), where x1 = 2 and y1 > 0.
OR
Find the intervals in which the function is (a) strictly increasing, (b) strictly decreasing.
Suppose a girl throws a die. If she gets 1 or 2, she tosses a coin three times and notes the number of tails. If she gets 3, 4, 5 or 6, she tosses a coin once and notes whether a 'head' or 'tail' is obtained. If she obtained exactly one 'tail', what is the probability that she threw 3, 4, 5 or 6 with the die?
Let Find a vector which is perpendicular to both . VIEW SOLUTION
Question 23
Using properties of determinants, prove that VIEW SOLUTION
Question 24
Using integration, find the area of the region in the first quadrant enclosed by the x-axis, the line y = x and the circle x2 + y2 = 32. VIEW SOLUTION
Question 25
Let A = {x ∈ Z : 0 ≤ x ≤ 12}. Show that
R = {(a, b) : a, b ∈ A, |a – b| is divisible by 4}is an equivalence relation. Find the set of all elements related to 1. Also write the equivalence class [2].
OR
Show that the function f : ℝ → ℝ defined by is neither one-one nor onto. Also, if g : ℝ → ℝ is defined as g(x) = 2x – 1, find fog(x). VIEW SOLUTION
Question 26
Find the distance of the point (–1, –5, –10) from the point of intersection of the line and the plane . VIEW SOLUTION
Question 27
A factory manufactures two types of screws A and B, each type requiring the use of two machines, an automatic and a hand-operated. It takes 4 minutes on the automatic and 6 minutes on the hand-operated machines to manufacture a packet of screws 'A' while it takes 6 minutes on the automatic and 3 minutes on the hand-operated machine to manufacture a packet of screws 'B'. Each machine is available for at most 4 hours on any day. The manufacturer can sell a packet of screws 'A' at a profit of 70 paise and screws 'B' at a profit of Rs 1. Assuming that he can sell all the screws he manufactures, how many packets of each type should the factory owner produce in a day in order to maximize his profit? Formulate the above LPP and solve it graphically and find the maximum profit. VIEW SOLUTION