Answer: The complex conjugate has a very special property. Consider what happens when we multiply a complex number by its complex conjugate. We find that the answer is a purely real number it has no imaginary part. This always happens when a complex number is multiplied by its conjugate the result is real number.

Real numbers can be positive or negative, and include the number zero. They are called real numbers because they are not imaginary, which is a different system of numbers

Step-by-step explanation: Every complex number has a complex conjugate. The complex conjugate of a + bi is a - bi. For example, the conjugate of 3 + 15i is 3 - 15i, and the conjugate of 5 - 6i is 5 + 6i.

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3 years ago

Determine whether each of these sets is countable or uncountable. For those that are countably infinite, exhibit a one-to-one co

iragen [17]

Answer:

Solution to determine whether each of these sets is countable or uncountable

Step-by-step explanation:

If A is countable then there exists an injective mapping f : A → Z+ which, for any S ⊆ A gives an injective mapping g : S → Z+ thereby establishing that S is countable. The contrapositive of this is: if a set is not countable then any superset is not countable.

(a) The rational numbers are countable (done in class) and this is a subset of the rational. Hence this set is also countable.

(b) this set is not countable. For contradiction suppose the elements of this set in (0,1) are enumerable. As in the diagonalization argument done in class we construct a number, r, in (0,1) whose decimal representation has as its i th digit (after the decimal) a digit different from the i th digit (after the decimal) of the i th number in the enumeration. Note that r can be constructed so that it does not have a 0 in its representation. Further, by construction r is different from all the other numbers in the enumeration thus yielding a contradiction

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3 years ago