Answer:
the equation only has 1 solution
Step-by-step explanation:
Its neither 2/8 is 1/4 simplified, therefore 2/8 is = 1/4
Hope this helped!
Let's use the variables N and Q for the number of nickels and the number of quarters.
We know there are 49 total coins, so we can write the following equation:
N + Q = 49
We can solve this equation for one variable which will help in the next step. Let's solve for N:
N = 49 - Q
Next, we know that nickels are worth $0.05 and quarters are worth $0.25. We can use these values along with the total value of $8.85 to create another equation.
0.05N + 0.25Q = 8.85
Now we can use substitution to solve our system out equations. We solved the first equation for N, so we can plug 49 - Q in for N.
0.05(49-Q) + 0.25Q = 8.85
Distribute and combine like terms.
2.45 - 0.05Q + 0.25Q = 8.85
2.45 + 0.2Q = 8.85
0.2Q = 6.4
Q = 32
Plug 32 in for Q in N + Q = 49 to find the number of nickels.
N + 32 = 49
N = 17
Dustin has 32 quarters and 17 nickels.
Hmm, the 2nd derivitve is good for finding concavity
let's find the max and min points
that is where the first derivitive is equal to 0
remember the difference quotient
so
f'(x)=(x^2-2x)/(x^2-2x+1)
find where it equals 0
set numerator equal to 0
0=x^2-2x
0=x(x-2)
0=x
0=x-2
2=x
so at 0 and 2 are the min and max
find if the signs go from negative to positive (min) or from positive to negative (max) at those points
f'(-1)>0
f'(1.5)<0
f'(3)>0
so at x=0, the sign go from positive to negative (local maximum)
at x=2, the sign go from negative to positive (local minimum)
we can take the 2nd derivitive to see the inflection points
f''(x)=2/((x-1)^3)
where does it equal 0?
it doesn't
so no inflection point
but, we can test it at x=0 and x=2
at x=0, we get f''(0)<0 so it is concave down. that means that x=0 being a max makes sense
at x=2, we get f''(2)>0 so it is concave up. that means that x=2 being a max make sense
local max is at x=0 (the point (0,0))
local min is at x=2 (the point (2,4))
