H = polar coordinates ([0 2 * pi], [01]); The radius of% ranges from 0 to 1.
Hold on;
Polar coordinates (t, sin(2*t). *cos(2*t),'-r ');
Mathematical definition of function: given a non-empty number, that is, A, apply the corresponding rule F to A and record it as f(A) to get another number, that is, B=f(A). Then this relationship is called functional relationship, or function for short.
Let the domain of the function f(x) be D, and the number set X is contained in D. If the number K 1 exists, so that f(x)≤K 1 holds for any x∈X, the function f(x) is said to have an upper bound on x, and K 1 is called the function f. If there is a number K2 that makes f(x)≥K2 hold for any x∈X, then the function f(x) has a lower bound on X, and K2 is called a lower bound on X. If there is a positive number M, then | f (x) |
The necessary and sufficient condition for the function f(x) to be bounded on X is that it has both upper and lower bounds on X.