f(x)=0 if x=0 or x is irrational, f(x)=1/q if x=p/q "in lowest terms", i.e., gcd(p,q)=1.
To see that it satisfies the claims, you simply need to verify that the limit as x approaches p is 0 for all p, which is pretty easy. From this both claims follow.
Sure! The definition of Laplace transform involves the integral of a function, which always makes discontinuous continuous.
An infinite sum of continuous functions does not have to be continuous. For example, you should be able to construct a Fourier series that converges to a discontinuous function.
Yes it can.
It means that the function value doesn't make sudden jumps. For example, a function that rounds a number down to the closest integer is discontinuous for all integer values; for instance, when x changes from 0.99 to 1, or from 0.999999 to 1, or for any number arbitrarily close to 1 (but less than one) to one, the function value suddenly changes from 0 to 1. At other points, the function is continuous.
yes it is a continuous function.
Sure! The definition of Laplace transform involves the integral of a function, which always makes discontinuous continuous.
An infinite sum of continuous functions does not have to be continuous. For example, you should be able to construct a Fourier series that converges to a discontinuous function.
Wherever a function is differentiable, it must also be continuous. The opposite is not true, however. For example, the absolute value function, f(x) =|x|, is not differentiable at x=0 even though it is continuous everywhere.
yes a discontinuous function can be developed in a fourier series
The numerator function x2 - 4 and the denominator function x2 + 3x + 2 are both continuous functions of x for the entire x-axis. However, the quotient of these two functions is not continuous when the denominator function has the value of 0, because division by zero is not defined. The denominator function is 0 when x = -1 or -2. Therefore, the quotient function is not fully continuous over any intervals that include -1 or -2, but it is "piecewise continuous" over other intervals of the x-axis.
A piece-wise continuous function is one which has a domain that is broken up inot sub-domains. Over each sub-domain the function is continuous but at the end of the domain one of the following possibilities can occur:the domain itself is discontinuous (disjoint domains),the value of the function is not defined at the start or end-point of the domain ((a hole),the value of the function at the end point of a sub-domain is different to its value at the start of the next sub-domain (a step-discontinuity).A piece-wise continuous function is one which has a domain that is broken up inot sub-domains. Over each sub-domain the function is continuous but at the end of the domain one of the following possibilities can occur:the domain itself is discontinuous (disjoint domains),the value of the function is not defined at the start or end-point of the domain ((a hole),the value of the function at the end point of a sub-domain is different to its value at the start of the next sub-domain (a step-discontinuity).A piece-wise continuous function is one which has a domain that is broken up inot sub-domains. Over each sub-domain the function is continuous but at the end of the domain one of the following possibilities can occur:the domain itself is discontinuous (disjoint domains),the value of the function is not defined at the start or end-point of the domain ((a hole),the value of the function at the end point of a sub-domain is different to its value at the start of the next sub-domain (a step-discontinuity).A piece-wise continuous function is one which has a domain that is broken up inot sub-domains. Over each sub-domain the function is continuous but at the end of the domain one of the following possibilities can occur:the domain itself is discontinuous (disjoint domains),the value of the function is not defined at the start or end-point of the domain ((a hole),the value of the function at the end point of a sub-domain is different to its value at the start of the next sub-domain (a step-discontinuity).
Yes it can.
It means that the function value doesn't make sudden jumps. For example, a function that rounds a number down to the closest integer is discontinuous for all integer values; for instance, when x changes from 0.99 to 1, or from 0.999999 to 1, or for any number arbitrarily close to 1 (but less than one) to one, the function value suddenly changes from 0 to 1. At other points, the function is continuous.
Yes. The cosine function is continuous. The sine function is also continuous. The tangent function, however, is not continuous.
An example of a function discontinuous everywhere fa(x) = 1 , if x belongs to set a fa(x) = 0 if x does not belong to set a The a is a subscript here. This function is called the 'Indicator function' and everywhere discontinuous.
That depends! The identity operator must map something from a space X to a space Y. This mapping might be continuous - which is the case if the identify operator is bounded - or discontinuous - if the identity operator is unbounded.
yes it is a continuous function.