# Algebra

This set of MATLAB Multiple Choice Questions & Answers (MCQs) focuses on “Algebra”.

1. What is the difference between syms ‘x’ and sym ‘x’?
a) there is no difference, they are the same functions
b) they are equivalent
c) syms ‘x’ makes the declaration long lasting while sym ‘x’ makes the declaration short lasting
d) syms ‘x’ makes the symbol short lasting while sym ‘x’ makes the declaration long lasting

2. What is the nature of the arrangement of the coefficients to store the following expression in MATLAB?

`y= 3x5 + x2 + 6`

a) y=[3,0,0,1,0,6]
b) y=[3,1,6]
c) y=[3;0;0;1;0;6]
d) y=[6,0,1,0,0,3]

3. In the function vpa(‘981’,10), why do we put 981 within inverted commas?
a) We can choose to not put the value within a pair of single inverted comma
b) We do it so that we don’t get an approximated value
c) We do it to get the exact value as MATLAB computes exact values, of numerical expressions, when declared within a string
d) We do it to get a floating-point approximated value, approximated to 14 digits

4. How would you simplify log(x20) – log(x13) – log(x7) in MATLAB? (Assume x is defined as a string variable)
a) simplify(log(x20)-log(x13)–log(x7));
b) log(x20) – log(x13) – log(x7)
c) simplify(log(x20)-log(x13)–log(x7),’IgnoreAnalyticConstraints’,true)
d) simplify(log(x20)-log(x13)–log(x7))

5. What happens if we don’t assign a variable to an expression which evaluates a numerical value?
a) MATLAB shows error
b) Nothing happens
c) The evaluated values are assigned to a variable ans automatically
d) Depends on the numerical value

6. MATLAB sees a ________ ordered variable as a vector of dimension n*1.
a) nth, (n+2)th
b) nth, (n+3)th
c) (n-1)th, nth
d) nth, (n-1)th

7. What will be the output for the below block of code?

`	P=[1 3 2]; r=roots(P);`

a) r=[-2,-2]
b) r=[-2 -1]
c) There is an error in the code
d)

```   r = -2
-1```

8. Name the functions used, for multiplication and division of two polynomials in MATLAB.
a) conv() and deconv()
b) mult() and div()
c) conv() and div()
d) mult and div

9. How can the formulation of polynomial be done from its roots?
a) poly(r), r is a row vector, containing the roots of the polynomial
b) poly([roots as a coloumn vector])
c) poly([roots as a row vector])
d) poly([roots in descending order as a coloumn vector])

10. The function to evaluate the value of a polynomial,l for a constant value of the independent variable(say a) in the polynomial is ______
a) poly(p,a), p is a row vector
b) polyder(p)
c) polyint(p)
d) polyval(c,a), c is a row vector