ans = quad(‘f(x)’ , a, b);

We know that, ∫x^n dx = (x^(n+1))/(n+1)
So ∫x^2 dx = (x^3)/3

f(x) = (x^3)/3 with lower limit = 2 
and upper limit = 3.
     = (3^3)/3 - (2^3)/3 
     = 19/3 
     = 6.3333

% MATLAB code for quad function
clc;
clear all;
ans = quad('x.^2',2,3);
disp(ans);

We know that, ∫sin(x)dx = -cos(x)

f(x) = -cos(x) with lower limit = 0
and upper limit = 3.14
    = -cos(3.14) - (-cos(0)) 
    = 1 + 1 
    = 2

% MATLAB code for quad function
ans = quad('sin(x)',0,3.14);
disp(ans);