0
The square of a negative number is the same as the square of its positive counterpart, aka its additive inverse ( [-2]2 = 22 = 4), so every positive number has two square roots, a positive one and negative one (both 2 and -2 are square roots of 4). However, the cube of any number will always have the same sign as the original number (23 = 8, [-2]3 = -8). This all follows from simple arithmetic with signs. The product of any two negative numbers is positive, as is the product of any two positive numbers, while the product of a negative number and a positive number is negative. All squares, by definition, are the product of either two positive numbers or two negative numbers, and in either case, the product must be positive. But a cube is the product of a number and its square (x3 = x * x * x = x2 * x). But we already know that the square must be positive, whether original number is positive or negative. So the sign of the original number determines the sign of the cube (because a positive number times a positive number is positive and a positive number times a negative number is negative). If you apply that rule in reverse, then the sign of the cube root must be the same as the sign of the number you are taking the cube root of.
Think of it this way. If you are trying to calculate the square root of a number, y, you are looking for another number, x, for which it is true that x * x = y. For any positive number y, there are always two values of x that satisfy that equation, with one being positive and the other being negative, but both having the same absolute value. And therefore, every positive number has two square roots.
On the other hand, if you are trying to find the cube root of a number, y, you are looking for a number, z, for which it is true that z * z * z = y. For any number, y, either positive or negative, there will be only one value of z that satisfies that equation. Therefore, every number, positive or negative, has just one cube root.
Actually, technically, once you get into higher mathematics, what is really going on is that every number has 3 cube roots, but they all just happen to have the same value. In fact, for any "degree" of root (square root, cube root, 4th root, 5th root, ... 100th root, ...) the number of roots of a number is exactly equal to the degree of the root (a number will have 4 4th roots, 5 5th roots, 10 10th roots, 99 99th roots, etc.) But, if the degree of the root is odd, then all of the roots will have the same value, while if the degree is even, the roots will be evenly split between two values that are the additive inverses of each other. For example, the 5th roots of -243 are -3, -3, -3, -3, and -3, while the 6th roots of 64 are 2, 2, 2, -2, -2, and -2.
Note also that negative numbers cannot have any roots of any even degree (square roots, 4th roots, 6th roots, etc.) Actually, even that's not true when you get into really advanced math. Even negative numbers have even-degree roots, it's just that the roots are not real numbers. They are "imaginary" numbers. This is, I'm sure, way beyond your level of education in mathematics, and I'm not trying to confuse you. But if I hadn't included these last two paragraphs, some wise-guy mathematician would come along and "correct" me, and in the process probably confuse you even more. For your purposes, however, just ignore the last two paragraphs.
Add your answer:
Earn +20 pts
What numbers come between the square root of 14?
The square roots of all non-negative numbers smaller than 14.
Where did square roots come from?
They came from geometry. If you have a square whose sides are 1 unit long then its diagonal is sqrt(2) units long.
How many x-intercepts can a cubic function have?
you can have either one or three x-intercepts, but now 2. because two real roots means 1 imaginary root which is not possible since imaginary roots come in pairs (2,4,6,8...)
Why do all numbers other than square numbers have an even number of factors?
Factors come in pairs. It is only in the case of a square number that the two middle factors are equal and so are counted only once.
Is a rhombus can be a square?
No. A square has to have 4 equal sides with interior angles of exactally 90 degrees. A rhombus has to have 4 equal sides only. (any angles (although to be the same length the angles come in pairs).)
How many roots in a radical problem if the index is odd?
An odd number. In the complex field, the number of roots is the same as the index. Complex (non-real) roots come in pairs (complex conjugates) so the number of real roots will also be odd.
What numbers come between the square root of 14?
The square roots of all non-negative numbers smaller than 14.
Where did square roots come from?
They came from geometry. If you have a square whose sides are 1 unit long then its diagonal is sqrt(2) units long.
What mathematicians came up with square roots and why?
Because the ancients were trying to find the measure of the diagonal of a square with sides of length one unit. The diagonal would not come out as any rational number and so irrational numbers - including square roots - had to be invented.
Do conures come in pairs?
Some Conures when you buy them do come in pairs but others they come individually.
Do chromosomes come in pairs?
Yes, chromosomes in humans come in pairs. Each individual has 23 pairs of chromosomes, with one of each pair inherited from each parent, for a total of 46 chromosomes.
How many x-intercepts can a cubic function have?
you can have either one or three x-intercepts, but now 2. because two real roots means 1 imaginary root which is not possible since imaginary roots come in pairs (2,4,6,8...)
Force always comes in?
Pairs they always come in pairs!
Do every polynomial function has at least one complex zero?
No. Complex zeros always come in conjugate pairs. So if a+bi is one zero, then a-bi is also a zero.The fundamental theorem of algebra says"Every polynomial equation of degree n with complex coefficients has n roots in the complex numbers."If you want to know how many complex root a given polynomial has, you might consider finding out how many real roots it has. This can be done with Descartes Rules of signsThe maximum number of positive real roots can be found by counting the number of sign changes in f(x). The actual number of positive real roots may be the maximum, or the maximum decreased by a multiple of two.The maximum number of negative real roots can be found by counting the number of sign changes in f(-x). The actual number of negative real roots may be the maximum, or the maximum decreased by a multiple of two.Complex roots always come in pairs. That's why the number of positive or number of negative roots must decrease by two. Using the two rules for positive and negative signs along with the fact that complex roots come in pairs, you can determine the number of complex roots.
When was The Roots Come Alive created?
The Roots Come Alive was created on 1999-11-02.
What is the relationship between the degree of a polynomial and the number of roots it has?
In answering this question it is important that the roots are counted along with their multiplicity. Thus a double root is counted as two roots, and so on. The degree of a polynomial is exactly the same as the number of roots that it has in the complex field. If the polynomial has real coefficients, then a polynomial with an odd degree has an odd number of roots up to the degree, while a polynomial of even degree has an even number of roots up to the degree. The difference between the degree and the number of roots is the number of complex roots which come as complex conjugate pairs.
Why do all numbers other than square numbers have an even number of factors?
Factors come in pairs. It is only in the case of a square number that the two middle factors are equal and so are counted only once.
