Answer:
No, Jude’s graph is incorrect. The inequality symbol is “less than,” so -9 is not included. He should have used an open circle on -9.
^ sample response
sorry that im late on this, but i hope it helps anyone else : )
22.5240 rounded to the nearest thousandth is 22.524. For this decimal
number to be rounded up rather than down, the original number would have
had to been 22.525 or higher.
I will say 1. All square roots are irrational.
Answer: Hello mate!
Clairaut’s Theorem says that if you have a function f(x,y) that have defined and continuous second partial derivates in (ai, bj) ∈ A
for all the elements in A, the, for all the elements on A you get:

This says that is the same taking first a partial derivate with respect to x and then a partial derivate with respect to y, that taking first the partial derivate with respect to y and after that the one with respect to x.
Now our function is u(x,y) = tan (2x + 3y), and want to verify the theorem for this, so lets see the partial derivates of u. For the derivates you could use tables, for example, using that:


and now lets derivate this with respect to y.
using that 

Now if we first derivate by y, we get:

and now we derivate by x:

the mixed partial derivates are equal :)