Divergence is easier to compute:
Curl is a bit more tedious. Denote by 
the differential operator, namely the derivative with respect to the variable 
. Then
![\mathrm{curl}\vec F=\left(D_y\left[y\tan^{-1}\dfrac xz\right]-D_z\left[e^{xy}\sin z\right]\right)\,\vec\imath-D_x\left[y\tan^{-1}\dfrac xz\right]\,\vec\jmath+D_x\left[e^{xy}\sin z}\right]\,\vec k](https://tex.z-dn.net/?f=%5Cmathrm%7Bcurl%7D%5Cvec%20F%3D%5Cleft%28D_y%5Cleft%5By%5Ctan%5E%7B-1%7D%5Cdfrac%20xz%5Cright%5D-D_z%5Cleft%5Be%5E%7Bxy%7D%5Csin%20z%5Cright%5D%5Cright%29%5C%2C%5Cvec%5Cimath-D_x%5Cleft%5By%5Ctan%5E%7B-1%7D%5Cdfrac%20xz%5Cright%5D%5C%2C%5Cvec%5Cjmath%2BD_x%5Cleft%5Be%5E%7Bxy%7D%5Csin%20z%7D%5Cright%5D%5C%2C%5Cvec%20k)
The correct answer is: [A]: " 2" .
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Explanation:
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5x - 4 = 3x ;
Subtract "3x" from each side of the equation;
5x - 4 - 3x = 3x - 3x ;
2x - 4 = 0 ;
Add "4" to each side of the equation;
2x - 4 + 4 = 0 + 4 ;
2x = 4 ;
Divide each side of the equation by "2" :
2x / 2 = 4 / 2 ;
x = 2 ; which is: "Answer choice: [A]: " 2" .
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Answer:
3 gallons of orange juice
THE FIRST ANSWER IS CORRECT
By asking students to answer un-biased, and with detail. Comparing and contrasting each others' genre preference is also useful.
