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Using long division, you can calculate that f(x)=( 2x^3 + 14x^2 + 7x - 29 ) / (2x^2 + 5 ) = Q(x) + ( R(x) / (2x^2 +5) )

The quotient Q(x) is ______

The remainder R(x) is _______

From this you can conclude that y=f(x) has an oblique (or slant) asymptote given by the line with equation y = R(x) or Q(x)

because lim as x approaches positive or negative infinity (R(x)) / (2x^2+5) = ______ .

1 Answer

4 votes

Answer:

The Quotient Q(x) is (x + 7)

The Remainder R(x) is (2x - 64)

Limit as x approaches negative or positive infinity (R(x)/(2x² + 5)) is 0

Explanation:

We want to use long division to determine the remainder and quotient in

(2x³+ 14x² + 7x - 29) / (2x² + 5)

This would be done step by step, as follows:

The denominator is written outside, and the numerator inside

We look for a number the when multiplied by the first expression of the funtion outside, gives the first expression of the funtion inside.

We multiply this function by the function outside, and write the resulting values under and subtract from the function inside.

The result is written, and the process is repeated, until the highest power of the function outside is greater the highest power of the function inside.

NOW, LET'S DO IT!

x times 2x = 2x³, so we choose x.

............... x

................................................

2x² + 5 | 2x³+ 14x² + 7x - 29

..............| 2x³ + 5x

..............| 14x² + 2x - 29

7 times 2x² gives 14x², we choose 7

...............x + 7

................................................

2x² + 5 | 2x³+ 14x² + 7x - 29

..............| 2x³ + 5x

..............| 14x² + 2x - 29

..............| 14x² + 35

..............| 2x - 64

We can't go further as the power of x inside is smaller than the power of x outside.

Therefore

Quotient Q(x) = x + 7

Remainder R(x) = 2x - 64

Limit as x approaches negative or positive infinity (R(x)/(2x² + 5))

= lim(x->±infty) (2x - 64) / (2x² + 5)

= 2lim(x->±infty) x(1 - 32/x) / x²(2 + 5/x²)

= 2(0)

= 0

User Thomas Boby
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