UNIVERSITY OF SRI JAYEWARDENEPURA FACULTY OF APPLIED SCIENCES
B.Sc. Degree First Year Second Semester Course Unit Examination - May 2022
                          DEPARTMENT OF MATHEMATICS
                                  MAT 122 2.0 Calculus
Time : Two hours           Number of Pages: 2/ Number of Questions: 5                 Total Marks: 100
                        Answer 4 questions(Question No 4 is complimentary)
  1. (a) The graph of f (x) is given below
            Fill in the following table
             c lim f (x) lim f (x)        lim f (x)   f (c)   f is cts at c
                 x→c−        x→c+         x→c
             0
             2
             4
      (b)                                      
                                               
                                                a2 x + 5a + 11, x < 2
                                               
                                       f (x) = 8                  x=2
                                                      2
                                                 3a
                                                        x + 5,    x>2
                                               
                                               
                                                    2
              i. Find all admissible value(s) for a such that lim f (x) is defined.
                                                                 x→2
             ii. Find all admissible value(s) for a such that f is continuous at 2.
      (c) Evaluate each of the following limits
                   x2 − 5x + 6
            i. lim     2
               x→3
                   √ x −9
                     x−2
           ii. lim
               x→4 x − 4
                                                                                         (25 points)
MAT 122 2.0                                - Page 2 of 2
  2. (a) Use the definition to find the derivative of f (x) = sin(x) at x = x0 .
      (b) State and prove Roller’s Theorem
      (c)     i. State Mean Value Theorem
             ii. Show that for any x > 4, there is a number ω between 4 and x such that
                                                  √
                                                    x−2      1
                                                         =
                                                   x−4      2ω
            iii. Use this fact to show that if x > 4 , then
                                                    √          x
                                                        x>1+
                                                               4
                                                                                    (25 points)
  3. Given
                                                   x3 5x2
                                         f (x) =     −    + 6x
                                                   3   2
      (a) Find all critical numbers.
      (b) Find where the function is increasing and decreasing.
      (c) Find the critical points and identify each as a relative maximum, relative minimum,
          or neither.
                                                                                    (25 points)
  4. (a) Using the definition prove that
                   1
           i. lim = 0
              n→∞ n
                   2n − 1    2
          ii. lim         =
              n→∞ 3n + 1     3
     (b) Let {an } and {bn } be convergent real sequences, and tn = an + bn for all but finitely
         many n show that
                                       lim tn = lim an + lim bn
                                         n→∞        n→∞        n→∞
      (c) show that if {sn } and {tn } are convergent real sequences, and sn ≥ tn for all n, then
           lim sn ≥ lim tn .
            n→∞      n→∞
                                                                                    (25 points)
                                  n
  5. Let s1 = 1 and let sn+1 =       (sn )2 for n ≥ 2.
                                 n+1
      (a) Prove that sn ≥ 0 for all n.
      (b) Prove that sn+1 ≤ sn for all n.
      (c) Show that sequence {sn } is convergent.
      (d) Show that lim sn = 0
                      n→∞
                                                                                    (25 points)