Answer with step-by-step explanation:
We are given that a function

Differentiate partially w.r.t x
Then, we get

Differentiate again w.r.t x

Differentiate function w.r.t y


Again differentiate w.r.t y

Differentiate partially w.r.t y




Hence, if f(x,y) is of class
(is twice continuously differentiable), then the mixed partial derivatives are equal.
i.e
3.) 5 packs of biscuits consumed a day
4.) Each person gets two chocolates or you could say 6 chocolates for every 3 people
5.) 15 songs played every two hours
Answer: m∠ M′N′O′ = 90 degrees
Step-by-step explanation: Hope that helps ! I am not sure if I am right but I think I am !
A trapezoid only has 1 line of symmetry
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