II Year Electronics and Computer Engineering, FoE, WUST

Scientific & Engineering Programming

II Year Electronics and Computer Engineering, FoE, WUST

Laboratory Class 9 – Matlab basics 2

The scope

To get familiar with Matlab interfaces, to define functions, conditionals, and loops, to learn graph plotting.

Prerequisites

Before the classes you should know, how to:

• define Matlab functions, compute their values,

• define conditionals,

• generate function plots.

Tasks

1. Find the roots of the polynomials (roots):

(a) x ² + x − 6, (b) x ³ + 3x ² − 4,

(c) x ⁴ − 2x ³ + x ² − 8x − 12, (d) x ⁵ − 3x ⁴ − 9x ³ + 31x ² − 36.

2. Define the functions f (x) = _x

^x ₊₁

, g(x, y) = p

25 − x ² − y ² , and h(x, y) = x + 2y xy



. Calcu- late f (5), g(1, 2), and h(f (3), 2).

3. Define the function f (x) which for its scalar argument returns absolute value of sine of it.

4. Define the function f (x) which for its scalar argument returns value of sine of it when it is positive, and zero otherwise.

5. Define the function mysing(x) which returns -1, 0, or 1, according as x is less than, equal to, or greater than 0.

6. Define the function mysum(x) which for its argument being a vector returns the sum of vector elements.

7. Define the function sumP ositive(x) which for its argument being a vector returns the sum of vector positive elements.

8. Define the function sumAll(x) which for its argument being a vector returns two separate values: the sums of positive, and the sum of negative vector elements.

9. Define the function mypoly(x, c) which for its arguments: a scalar x and a vector (c 1 , c 2 , c 3 , . . .) evaluate a polynomial c 0 + c 1 x + c 2 x ² + c 3 x ³ + . . . and returns its value.

1

Scientific & Engineering Programming, II Year EaCE, FoE, WrUST 2

10. Define the function gcd(m, n) that implements the Euclidean algorithm for finding the great- est common divisor of m and n.

11. Plot functions defined in the tasks 2–5.