Hello,
y=2xe^x
y'=2(e^x+xe^x)=2(x+1)e^x
y''=2(e^x+(x+1)e^x)=2(x+2)e^x
x |-infinite -2 0 +infinite
e^x | ++++++++++++++++++
x+2 |------------0 +++++++++++
y'' | -----------0 +++++++++++
y''<0 if x<-2
<span>The interval on which the graph is concave down is (-infinite -2[</span>
Because this shape has 2 right angles, we can confirm that it has one set of parallel sides and is a trapezoid. Therefore, use the formula for area of a trapezoid, .5(b1+b2)(h)
.5(1+6)(12)
.5(7)(12)
42 units^2
Isn’t it supposed to be a minus sign? For it can be like w-2, w-2 ?
Answer:
- 6 2/3 qt 80%
- 13 1/3 qt 20%
Step-by-step explanation:
It is often convenient to solve a mixture problem by letting a variable represent the quantity of the higher-concentration contributor to the mix.
__
We can let x represent the number of quarts of 80% solution needed. Then (20-x) is the number of quarts of 20% solution needed. The amount of salt in the final mix is ...
0.80x +0.20(20-x) = 0.40(20)
0.60x = 0.20(20) . . . . . . . . subtract 0.20(20) and simplify
x = 20/3 = 6 2/3 . . . . . . . . . divide by 0.60; quarts of 80% solution
(20 -x) = 13 1/3 . . . . . . . . . . amount of 20% solution needed
The teacher should mix 6 2/3 quarts of 80% solution with 13 1/3 quarts of 20% solution.
Answer:
Step-by-step explanation:
If given tables in the picture show the proportional relationship,
Number of wheels (w) ∝ Number of buses (b)
w ∝ b
w = kb
Here, k = proportionality constant
k = 
Number of buses (b) Number wheels (w) Wheels per bus 
5 30
8 48 
10 60 
15 90 
Here, proportionality constant is 6.
Similarly, If number of wheels (w) ∝ Number of train cars (t)
w = kt
Here, k = proportionality constant
k = 
Number of train cars(t) Number of wheels(w) Wheels per train car (
)
20 184 
30 264 
40 344 
50 424 
Since, ratio of w and t is not constant, relation between number of wheels and number of train cars is not proportional.