sol 4th polynomial questions
Answers
On dividing x³-3x²+x+2 by a polynomial g(x),the quotient and remainder were x-2 and -2x+4 respectively.find g(x)
f(x) = x³ - 3x² + x + 2
q(x) = x - 2
let say
g(x) = ax² + bx + c
r = - 2x + 4
f(x) = g(x)q(x) + r
=> x³ - 3x² + x + 2 = (ax² + bx + c)(x - 2) + (-2x + 4)
=> x³ - 3x² + x + 2 = ax³ + x²(b - 2a) + x(c - 2b) -2c -2x + 4
=> x³ - 3x² + x + 2 = ax³ + x²(b - 2a) + x(c - 2b - 2) + (-2c + 4)
Equating Power terms
a = 1
b - 2a = - 3
=> b -2 = -3
=> b = -1
c - 2b - 2 = 1
=> c + 2 - 2 = 1
=> c = 1
⇒ -2c + 4 = 2
=> -2c = -2
=> c = 1
g(x) = x² - x + 1
(Ans): g(x) = x² - x + 1
An algebraic expression with the combination of different variables and constant terms where the power of each real number is a non negative integer is what we call as polynomial.
Examples include : (√3z² - 5z + 6), (x -2), etc,.
There are different types of polynomials. Some of these are :
» Linear polynomial, of degree or power 1
» Quadratic polynomial, of degree or power 2, etc.
Let the given polynomial = p(x)
quotient = q(x) and remainder = r(x)
From the Euclids division lemma,
Dividend = (Divisor)(Quotient) + Remainder
i.e., p(x) = [g(x)][q(x)] + r(x)
On substituting all the given values,
g(x) = x^2 - x + 1
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Therefore, required g(x) = x^2 - x + 1
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For the exact calculations, refer to the attachment.