If f(x) = 3x2 - 6, find f(-1) .<br> f(-1)=

seventy percent of the 100 students in a middle school cafeteria bought their lunch. Some of the students that bought their lunc

MAVERICK [17]

100% -60% is equal to 40%

so 40% of the students remained in the cafeteria

6 0

3 years ago

A model for the movement of a stock supposes that if the present price of the stock is s, then, after one period, it will be eit

aleksklad [387]

Answer:

$P(X\geq 470)=0.9991$

Step-by-step explanation:

Present price of stock is s, if x is the times that the stock increases (by u) among the 1000 periods we can calculate the price after 1000 periods as follows:

$s*u^n*d^{(1000-x)}$ note that if the price increase n periods, so it should decreases in the other 1000-x periods.

We need that the price be 30% higher or 1.3 times the initial price. That requirement is expressed as follows:

$s*u^n*d^{(1000-x)}>1.3s$

applying properties of exponents and reorganizing.

$d^{1000}(\frac{u}{d})^x>1.3$

solving for x

$1000 log(d)+ x log (\frac{u}{d})>log(1.3)$

$x >\frac{log(1.3)-1000 log(d)}{log (\frac{u}{d})}$

Using the values given d= 0.99 and u=1.012

$x > 469.208967$

So, we need at least 470 increase periods

Now we can calculate the probability of have 470 increase periods or more, taking into account that the distribution of x is binomial, the period can be and increase period with 0.52 of probability and we have 1000 total trials.

The formula for the binomial cumulative probability function is

$F(x;p,n) = \Sigma_0^x \left(\begin{array}{c}n&i\end{array}\right)p^i(1-p)^{n-i}$

With this formula we can calculate the probability of obtain x successful trials or less ( $P(X\leq x)$ ). There, p is the probability of success (probability of increase period in this case), x is the maximum number of successful trials, n the number of total trials. We should calculate F with x=470, p=0.52 and n= 1000. The result is $P(X\leq x)$ , but we need $P(X\geq x)$ so we can calculate that probability as

$P(X\geq x)=1-P(X\leq x)$

In order to calculate the cumulative function we can use excel function BINOM.DIST

BINOM.DIST(x,trials,probability,cumulative)

BINOM.DIST(470,1000,0.52,TRUE)

We obtain that $P(X\leq 470)=0.00087$ , so $P(X\geq 470)=1-0.00087=0.9991$

7 0

2 years ago

Find the error and correct it

jek_recluse [69]

4=-2(x-3)

divide both sides by 2

2=-(x-3)

remove parentheses

2=-x+3

move terms

2+x=3

subtract numbers

x=3-2

x=1

6 0

2 years ago

Write the expression 2a+b in the form of a fraction with the given denominator. Check if the domain of the expression changed. I

Ymorist [56]

Answer:

See below

Step-by-step explanation:

I will assume the given denominator is 3a as there is nothing attached to the statement.

Lets first look at the domain of 2a+b. As it is a polynomial with unknowns a and b, we know it has its domain in all real numbers for both a and b as every polynomial does. For verifying it replace a and b by any real number you can think of.

Domain = a, b belonging to R

Now, if we divide 2a+b by 3a we will have:

(2a+b)/3a

As know we don not have a polynomial we cant state that the domain will still be all the real numbers for sure. We need to go further.

We have a fraction and as every fraction the denominator CAN'T be equal to 0, so 3a MUST be different to 0. This means that a MUST be different to 0. So, now our domain changes:

domain' = a, b belonging to R and a different to 0.

6 0

3 years ago

URGENT PLEASE ANSWER QUICKLY!!!!!!!! (WILL MARK BRAINLYIST)

mina [271]

Answer:

for 10 people she makes 35$

for 20 people she makes 55$

for 30 people she makes 75$

and for 40 people she makes 95$

Step-by-step explanation:

just plug the number of people (10, 20, 30, 40) into the x in the equation.

3 0

2 years ago

If f(x) = 3x2 - 6, find f(-1) . f(-1)=