Answer:
dz / dt = -50
Step-by-step explanation:
To solve the chain rule must apply, we have all the necessary values to make the calculation, as follows:
using the chain rule, we find:
dz / dt = (∂z / ∂x) * (∂x / ∂t) + (∂z / ∂y) * (∂y / ∂t)
Evaluating when t = 9, we have to:
fx (6, 4) * g '(9) + fy (6, 4) * h '(9)
We know that g '(9) = −6; h '(9) = 4; fx (6, 4) = 9; fy (6, 4) = 1
Replacing:
(9 * -6) + (1 * 4) = -50
Por lo tanto dz / dt = -50
 
        
             
        
        
        
402.25 * 10 = 4,022.5   Since there are five days and 10 laps per day, just multiply the second number by five    4,022.5 * 5  = 20,112.5 meters
        
             
        
        
        
Answer:
1)option b
2)option a
Step-by-step explanation:
1) circumference = 62.8 in
 => 2πr= 62.8
 => r= 62.8/(2×3.14)= 10 in
diameter = 2×10 in = 20 in
2)diameter = 14m
radius = 7 m
Area of the circle= πr² =3.14(7)²=3.14×49 
= 153.86
 =153.9 m²
 
        
                    
             
        
        
        
Answer: Choice D
Explanation:
The increase of 9.8% rounds to 10% when rounding to the nearest ten
An increase of 10% would use the multiplier 1.1
Think of it like saying 1 + 0.10 = 100% + 10%
Similarly, the 5.1% rounds to 5% and an increase of this amount will use the multiplier 1.05
So if we started with 20 items, then 20(1.1)(1.05) is the expression that estimates an increase of 10% followed by an increase of 5%. The order doesn't matter (so you could increase by 5% first, then 10% later).