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secondary 3 | A Maths
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need help with second part
Date Posted: 3 years ago
Views: 170
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done
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In the question, f(x) is divisible by (x-2) and (x+1). Therefore f(x) is to be divided by (x-2) and (x+1). (Long division method)
Date Posted:
3 years ago
The function is divisible by (x - 2)(x + 1) .
It is faster to first expand to get x² - x - 2, perform a single long division, as opposed to dividing twice
It is faster to first expand to get x² - x - 2, perform a single long division, as opposed to dividing twice
Also, long division may not be necessary once the factor x² - x - 2 is obtained, since it can be easily figured out from the coefficient of x⁴ and the term independent of x that the factor is x² + cx + 6.
(Since only x² × x² can give x⁴ and only 6 × -2 can give -12)
By comparing the term in x³,
x²(cx) - x(x²) = 4x³
cx³ - x³ = 4x³
cx³ = 5x³
c = 5
(Since only x² × x² can give x⁴ and only 6 × -2 can give -12)
By comparing the term in x³,
x²(cx) - x(x²) = 4x³
cx³ - x³ = 4x³
cx³ = 5x³
c = 5
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