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4 Questions about The Polynomial Remainder Theorem

4 Questions about The Polynomial Remainder Theorem-example-1
4 Questions about The Polynomial Remainder Theorem-example-1
4 Questions about The Polynomial Remainder Theorem-example-2
4 Questions about The Polynomial Remainder Theorem-example-3
4 Questions about The Polynomial Remainder Theorem-example-4
User Vardhan
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1 Answer

5 votes

None of these questions have anything to do directly with the polynomial remainder theorem. The theorem says that the remainder upon dividing a polynomial
p(x) by
x-c is given by the value of
f(c).

For these questions, all you really have to do is evaluate the given polynomials at the given points, and IMO is much less work.

Question 2:
f(5)=4(5)^2-5(5)+2=77

Question 3:
f(4)=3(4)^4-8)4)^2-2(4)+12=644

Question 4: Here you have check the value of
h(x) and 2 and -2, then interpret them as points in the coordinate plane,
(x,h(x)).


h(-2)=2(-2)^5-4(-2)^4-2(-2)^2+15=-121


h(2)=2(2)^5-4(2)^4-2(2)^2+15=7

Question 5: Same as in question 4, but you have to check
h(x) at -4, -3, -2, -1.


h(-4)=72


h(-3)=46


h(-2)=26


h(-1)=12

- - -

If you insist on using the polynomial remainder theorem, it's a question of polynomial division. For instance, in question 2 you'd compute


(4x^2-5x+2)/(x-5)=4x+15+(77)/(x-5)\implies4x^2-5x+2=(4x+15)(x-5)+77

so the remainder is 77, as we found by simply computing
f(5).

User Priyashree Bhadra
by
7.9k points