So since the vertex falls onto the axis of symmetry, we can just solve for that to get the x-coordinate of both equations. The equation for the axis of symmetry is , with b = x coefficient and a = x^2 coefficient. Our equations can be solved as such:
y = 2x^2 − 4x + 12:
y = 4x^2 + 8x + 3:
In short, the vertex x-coordinate's of y = 2x^2 − 4x + 12 is 1 while the vertex's x-coordinate of y = 4x^2 + 8x + 3 is -1.
Answer: first choice, exponential, because there is a relatively consistent multiplicative rate of change.
Explanation:
1) I have attached the figure with the data table that represents the temperature of a cup of coffee over time.
These are the data:
Time (min) ------ Temperature (°F)
0 ----------------------- 200
10 ---------------------- 180
20 --------------------- 163
30 --------------------- 146
40 ---------------------131
50 -------------------- 118
60 -------------------- 107
2) Since, the increase in time is constant, while the decrease in temperaute is not, you know that it is not linear.
3) The other two options involve exponential models.
The exponential models have a constant multiplicative rate of change, not additive. Therefore, the only feasible choice is the first one: temperature of a cup of coffee over time.
4) You can prove it:
i) Exponential models have the general form y = A [r]ˣ, where B is r is the multiplicative rate of change: any value is equal to the prior value multiplied by r:
y₁ = A [r]¹
y₂ = A[r]²
y₂ / y1 = r ← as you see this is the constant multiplicative rate of change.
ii) Test some data:
180 / 200 = 0.9
163 / 180 ≈ 0.906 ≈ 0.9
146 / 163 ≈ 0.896 ≈ 0.9
131 / 146 ≈ 0.897 ≈ 0.9
118 / 131 ≈ 0.901 ≈ 0.9
107 / 118 ≈ 0.907 ≈ 0.9
As you see all the data of the table have a relatively consistent multiplicative rate of change, which proves that the temperature follows an exponential decay; so the right choice is the first one.
Answer:
Step-by-step explanation:
Biquadratic Equation
It's a fourth-degree equation where the terms of degree 1 and 3 are missing. It can be solved for the variable squared as if it was a second-degree equation, and then take the square root of the results
Our equation is
If we call , our equation becomes a second-degree equation
Dividing by -3
Factoring
It leads to these solutions
Taking back the change of variable, we have for the first solution
Now for the second solution, we get imaginary (complex) values
Summarizing, the four solutions for x are
Answer:
B. 6.3%
Step-by-step explanation:
For each time that the coin is tosse, there are only two possible outcomes. Either it comes up tails, or it does not. The probability of coming up tails on a toss is independent of any other toss. So we use the binomial probability distribution to solve this question.
Binomial probability distribution
The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.
In which is the number of different combinations of x objects from a set of n elements, given by the following formula.
And p is the probability of X happening.
Fair coin:
Equally as likely to come up heads or tails, so
Probability that the first tails comes up on the 4th flip of the coin?
0 tails during the first three, which is P(X = 0) when n = 3.
Tails in the fourth, with probability 0.5. So
0.0625 * 100 = 6.25%
Rounding to the nearest tenth of a percent, the correct answer is:
B. 6.3%