Constant equals sign is usually used when some parameter variables are constants or constant expressions, which always means that the relationship has nothing to do with the variables.
For example, the function f(x)≡k means that no matter what the value of x is, the value of this function is always k.
It can also represent congruence symbols, which are used in congruence formulas. Suppose m is a positive integer greater than 1, and a and b are integers. If m|(a-b), a and b are said to be congruent with respect to the module m, and denoted as a≡b(mod M).
Extended data:
The Multipurpose of "Constant equals" and the Identity of Polynomials.
Let f(x) and g(x) be two polynomials with the same variable x, and f(x)≡g(x) represents the identities of these two polynomials. That is to say, no matter what real value is substituted into the left and right sides of x, the equation always holds.
Properties of identity: If two polynomials are the same, the coefficients of the same term on the left and right sides are equal.
That is a0xn+a1xn-1+...+an-1x+an = b0xn+b1xn-1+...+bn-1x+.
So what? a0=b0，a 1=b 1，…，an- 1=bn- 1，an=bn .
Baidu Encyclopedia-VIII
Baidu encyclopedia-equal sign