多项式是那些包含变量,系数和常数的代数表达式。例如,在多项式8x 2 + 3z – 7中,在这个多项式中,8,3是系数,x和z是变量,而7是常数。正如将简单的数学运算应用于数字一样,这些运算也可以应用于不同的多项式,对多项式应用不同的运算会得出一个新的多项式,例如p(x)是一个乘以q(x)的多项式,然后是新的多项式g(x)= p(x)×q(x)。
多项式的除法算法
除法算法指出,
If p(x) and g(x) are two polynomials with g(x) ≠ 0, then we can find polynomials q(x) and r(x) such that,
p(x) = g(x) x g(x) + r(x)
Where r(x) = 0 or degree of r(x) < degree of g(x)
Dividend = Quotient × Divisor + Remainder
让我们看一下进行这种划分的一些步骤,然后解决一些与之相关的示例。
- 在此步骤中,将除数和除数按照其程度递减的顺序排列。
- 商的第一项是通过将除数的最高项除以除数的最高项来得出的。
- 商的第二项是通过将获得的新除数的最高程度项除以除数的最高程度项而获得的。
- 继续此过程,直到余数小于除数。
让我们看一下与此算法有关的一些示例问题。
问题1:将多项式x 3 + x 2 – 1除以x – 1。
解决方案:
We just need to follow the same steps as mentioned above.
So, the quotient here is x2 + 2x + 2 and remainder is 1.
问题2:将多项式x 4 + x 3 + x 2 – 1除以x 3 – 1。
解决方案:
So, the quotient comes out to be x + 1 and the remainder x2 + x.
使用除法算法查找多项式的零点
假设我们有一个次数为3的多项式P(x)=0。如果给定该多项式的根x = r。我们可以通过将多项式除以(x -r)来找到其他两个根。让我们看一个例子。
问题1:如果根之一是,则找出多项式f(x)= 2x 3 -5x 2 -4x + 3的所有零点 。
解决方案:
x = is a root of the polynomial (Given)
Now we know from the fact stated above, (x – ) is a factor of the given polynomial. So, for finding out the other zeros, we need to divide the polynomial with this factor.
So we get 2x2 -4x – 6 as quotient.
The remaining two roots are roots of this polynomial.
2x2 – 4x – 6 = 0
⇒ 2x2 -6x + 2x – 6 = 0
⇒ 2x(x – 3) + 2 (x – 3) = 0
⇒ (2x + 2) (x – 3) = 0
x = -1 and x = 3
Thus, the remaining two roots are x = -1 and x = 3.
问题2:将多项式5x 4 -3x 3 + 2x 2 – 1除以x 3 – 1。
解决方案:
The remainder is 3 and quotient is 5x3 + 2x2 + 4x + 4
问题3:找出2x 4 – 3x 3 -3x 2 + 6x – 2的所有零。我们知道两个零分别是√2和-√2。
解决方案:
We are given two zeros of the polynomial. We know that, x – √2 and x + √2 are the factors of the polynomial.
Two find the other roots let’s divide the polynomial with both of these.
(x – √2)(x + √2)
= x2 – 2
Dividing the polynomial with x2 – 2.
The quotient polynomial is given by 2x2 – 3x + 1
The remaining two roots are also the roots of this polynomial.
2x2 – 3x + 1
⇒ 2x2 – 2x -x + 1
⇒ 2x(x -1) -1(x – 1)
⇒ (2x – 1) (x – 1) = 0
So, the roots come out to be x = and x= 1.
Thus, all the roots are x = 1, √2, -√2 and