Look at the picture......
Answer with explanation:
Let us assume that the 2 functions are:
1) f(x)
2) g(x)
Now by definition of concave function we have the first derivative of the function should be strictly decreasing thus for the above 2 function we conclude that
![\frac{d}{dx}\cdot f(x)](https://tex.z-dn.net/?f=%5Cfrac%7Bd%7D%7Bdx%7D%5Ccdot%20f%28x%29%3C0%5C%5C%5C%5C%5Cfrac%7Bd%7D%7Bdx%7D%5Ccdot%20g%28x%29%3C0)
Now the sum of the 2 functions is shown below
![y=f(x)+g(x)](https://tex.z-dn.net/?f=y%3Df%28x%29%2Bg%28x%29)
Diffrentiating both sides with respect to 'x' we get
![\frac{dy}{dx}=\frac{d}{dx}\cdot f(x)+\frac{d}{dx}\cdot g(x)\\\\](https://tex.z-dn.net/?f=%5Cfrac%7Bdy%7D%7Bdx%7D%3D%5Cfrac%7Bd%7D%7Bdx%7D%5Ccdot%20f%28x%29%2B%5Cfrac%7Bd%7D%7Bdx%7D%5Ccdot%20g%28x%29%5C%5C%5C%5C)
Since each term in the right of the above equation is negative thus we conclude that their sum is also negative thus
![\frac{dy}{dx}](https://tex.z-dn.net/?f=%5Cfrac%7Bdy%7D%7Bdx%7D%3C0)
Thus the sum of the 2 functions is also a concave function.
Part 2)
The product of the 2 functions is shown below
![h=f(x)\cdot g(x)](https://tex.z-dn.net/?f=h%3Df%28x%29%5Ccdot%20g%28x%29)
Diffrentiating both sides with respect to 'x' we get
![h'=\frac{d}{dx}\cdot (f(x)\cdot g(x))\\\\h'=g(x)f'(x)+f(x)g'(x)](https://tex.z-dn.net/?f=h%27%3D%5Cfrac%7Bd%7D%7Bdx%7D%5Ccdot%20%28f%28x%29%5Ccdot%20g%28x%29%29%5C%5C%5C%5Ch%27%3Dg%28x%29f%27%28x%29%2Bf%28x%29g%27%28x%29)
Now we can see the sign of the terms on the right hand side depend on the signs of the function's themselves hence we remain inconclusive about the sign of the product as a whole. Thus the product can be concave or convex.
10u + t is the expressions shows the value of the reversal of digits in a two digit number, t = the tens digit and u = the ones digit. This can be obtained by multiplying 10 with the tens digit and adding unit digit.
<h3>Which is the required expressions?</h3>
Given that, in a two digit number,
t = the tens digit
u = the ones digit
The expression for the digit will be ,
10×t + u = 10t + u
The value of its reversal,
u = the tens digit
t = the ones digit
10×u + t = 10u + t is the required expression
For example,
37 = 10×3 + 7 = 30 + 7 and its reverse 73 = 10×7 + 3 = 70 + 3
Hence 10u + t is the expressions shows the value of the reversal of digits in a two digit number, t = the tens digit and u = the ones digit.
Learn more about algebraic expressions here:
brainly.com/question/19245500
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The answer I believe is 10 calories per minute because 20 x30 =600 I did that because she burned 20 calories per minute so with that being said there’s 60 minutes is the maximum minutes any time can go to so you do 600 divided by 60 which equals 10 which means she burns 10 calories per minute hope this is right