I agree. The answer is choice B

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f ' (1) is shown to be positive
f ' (2) is shown to be positive as well
There are no critical values between x = 1 and x = 2, so f ' (x) is positive on the interval 1 < x < 2, so f(x) is increasing on this interval

All of this points to either choice A or choice B

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Similarly,
f ' (3) is negative
f ' (4) is negative
so f ' (x) is negative where 3 < x < 4 due to no other critical values being between x = 3 and x = 4

Based on these facts alone, the answer is either choice B or choice D

But we know that it can't be choice D as we determined it was between A and B. This rules out choice D

So all that's left is choice B

6 0

4 years ago

Find the work done by a force fâ =1.8i^+2.2j^n as it acts on an object moving from the origin to the point râ =56i^+31j^m.

Mama L [17]

Take the dot product:

$W=\mathbf F\cdot\mathbf r=(1.8\,\mathbf i+2.2\,\mathbf j)\cdot(56\,\mathbf i+31\,\mathbf j)$
$W=169\,\text{Nm}$

8 0

3 years ago