Since the divisor is of 3rd order, the reminder has to be
of 2nd order.
r=ax^2 + bx +
c
We 'll write the reminder
theorem:
f=g*q + r, where q is the quotient of the
division.
We notice that x=1 is a multiple root of the
polynomial g.
f(1)=g(1)*q(1) +
r(1)
By substituting the value x=1 into all polynomials,
we'll obtain:
f(1)= 1^5 + 1^4 +
1
f(1)=1+1+1
f(1)=3
g(1)=
(1-1)^3=0
r(1)=a+b+c
So, we'll
have:
3=0*q(1) +
a+b+c
3=a+b+c
Because of the
fact that x=1 is a multiple root, it will cancel the first derivative of the expression:
f=g*c + r
f' =(g*c)' + r'
5x^4
+4 x^3=3*(x-1)^2*q+(x-1)^3*q' +2*ax+ b
By substituting the
value x=1 into all polynomials, we'll
obtain:
5+4=2*a+b
9=2*a+b
We'll
calculate the first derivative of the expression
5x^4 +4
x^3=3*(x-1)^2*q+(x-1)^3*q' +2*ax+ b
(5x^4 +4
x^3)'=(3*(x-1)^2*q+(x-1)^3*q' +2*ax+ b)'
5*4* x^3 + 4*3*
x^2=6*(x-1)*q+3*(x-1)^2*q'+3*(x-1)^2*q'+(x-1)^3*q"+2a
By
substituting the value x=1 into all polynomials, we'll
obtain:
20+12=2*a
We'll divide
by 2:
a = 10 + 6
a =
16
2a+b=9
2*16 + b =
9
b = 9 - 32
b =
-23
a+b+c =
3
16-23+c=3
-7+c=3
c=3+7
c=10
The
reminder is: 16x^2 - 23x + 10
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