I'll use subscript notation for brevity, i.e.
.
By the chain rule,



We have

and

When
, we have

and the partial derivatives take on values of

So we end up with

Given functions are


The total number of ducks and swans in the lake after n months can be determined by adding the functions s(n) and d(n).





Taking 2 as common, we get

Hence The total number of ducks and swans in the lake after n months is
Answer:
1. 125
2. 25
3. 40
4. 39
First question:
(15-10)^2 + (15-5)^2
parentheses first to get 5^2 + (15-5)^2
exponents next to get 25 + (15-5)^2
parentheses again 25 + 10^2
exponents again 25 + 100 = 125
Second question:
simplify the exponents (3 *3) + (4 * 4) + (2 * 2) to get 9 + 16 + 4 = 29
Third question:
simplify in the parentheses 6 1/7 - 1/7 = 6
divide 60 by 6 to get 10
multiply 10 by 4 to get 40!
Fourth question:
simplify the fractions to get 1/3 + 8/3 = 3
multiply the 3 by 13 to get 39
Answer:
D
Step-by-step explanation:
(-2 1/2, -3) = (-5/2 , -3) & (1, -3)
![Distance=\sqrt{(x_{2}-x_{1})^{2}+(y_{2}-y_{1})^{2}}\\\\ =\sqrt{(1-[\frac{-5}{2}])^{2}+(-3-[-3])^{2}}\\\\ =\sqrt{(1+\frac{5}{2})^{2}+(-3+3)^{2}}\\\\ =\sqrt{(\frac{7}{2})^{2}} \\\\=\frac{7}{2}\\\\=3\frac{1}{2}](https://tex.z-dn.net/?f=Distance%3D%5Csqrt%7B%28x_%7B2%7D-x_%7B1%7D%29%5E%7B2%7D%2B%28y_%7B2%7D-y_%7B1%7D%29%5E%7B2%7D%7D%5C%5C%5C%5C%20%3D%5Csqrt%7B%281-%5B%5Cfrac%7B-5%7D%7B2%7D%5D%29%5E%7B2%7D%2B%28-3-%5B-3%5D%29%5E%7B2%7D%7D%5C%5C%5C%5C%20%3D%5Csqrt%7B%281%2B%5Cfrac%7B5%7D%7B2%7D%29%5E%7B2%7D%2B%28-3%2B3%29%5E%7B2%7D%7D%5C%5C%5C%5C%20%3D%5Csqrt%7B%28%5Cfrac%7B7%7D%7B2%7D%29%5E%7B2%7D%7D%20%5C%5C%5C%5C%3D%5Cfrac%7B7%7D%7B2%7D%5C%5C%5C%5C%3D3%5Cfrac%7B1%7D%7B2%7D)