Answer:
1.
Let f and g concave functions. Then for a in (0,1), and
Now,
This shows that the function f+g is concave.
2. Let f and g concave functions.
This shows that the product of two concave functions isn't concave.
Since it is odd, 4, 6 and 10 cannot be divisors.
5 cannot be a divisor since when you count by 5's you get numbers ending in 5 or 0
(5,10,15,20, etc)
9 cannot be a divisor since 9 x 6 = 54 and 9 sx 7 = 63
None of your answers will work with 57.
3 will work even though you did not list it. 5+7 = 12 and 1+2 = 3. If the sum of the digits = 3, 6 or 9, the number is divisible by 3.
45 is divisible by 3 (4+5=9)
78 is divisible by 3 (7+8=15 and 1+5 = 6)
Answer:
12.6
Step-by-step explanation:
We can start by finding the area of the rectangle
13x4=52
Now the semicircles, the diameter of the circle is 4, so the radius is 2 to find the area we do
pi x 2=6.3
6.28^2=39.4
since there are two circles we can just add them together instead of dividing the answer above by 2, now we can subtract this from 52
52-39.4=12.6