Please help meeee!?!?!?!?!?!??!?!??

For what value of x is the figure a rhombus

irinina [24]

Check the picture below.

7 0

3 years ago

The brand manager for a brand toothpaste must plan a campaign designed to increase brand recognition. He wants to first determin

bulgar [2K]

We need to find out how many adults must the brand manager survey in order to be 90% confident that his estimate is within five percentage points of the true population percentage.

From the given data we know that our confidence level is 90%. From Standard Normal Table we know that the critical level at 90% confidence level is 1.645. In other words, $Z_{Critical}=1.645$ .

We also know that E=5% or E=0.05

Also, since, $\hat{p}$ is not given, we will assume that $\hat{p}$ =0.5. This is because, the formula that we use will have $\hat{p}(1-\hat{p})$ in the expression and that will be maximum only when $\hat{p}$ =0.5. (For any other value of $\hat{p}$ , we will get a value less than 0.25. For example if, $\hat{p}$ is 0.4, then $1-\hat{p}=0.6$ and thus, $\hat{p}(1-\hat{p})=0.24$ .).

We will now use the formula

$n=(\frac{Z_{Critical}}{E})^2\hat{p}(1-\hat{p})$

We will now substitute all the data that we have and we will get

$n=(\frac{1.645}{0.05})^2\times0.5(1-0.5)$

$n=(32.9)^2\times0.25$

$n=270.6025$

which can approximated to n=271.

So, the brand manager needs a sample size of 271

3 0

3 years ago

Need help and explain please!!

lukranit [14]

Answer:

$x=-4\text{ and } x=3$

Step-by-step explanation:

We are given the second derivative:

$g''(x)=(x-3)^2(x+4)(x-6)$

And we want to find its inflection points.

To do so, we will first determine possible inflection points. These occur whenever g''(x) = 0 or is undefined.

Next, we will test values for the intervals. Inflection points occur if and only if the sign changes before and after the point.

So first, finding the zeros, we see that:

$0=(x-3)^2(x+4)(x-6)\Rightarrow x=-4, 3, 6$

So, we can draw the following number-line:

<----(-4)--------------(3)----(6)---->

Now, we will test values for the intervals x < -4, -4 < x < 3, 3 < x < 6, and x > 6.

Testing for x < -4, we can use -5. So:

$g^\prime^\prime(-5)=(-5-3)^2(-5+4)(-5-6)=704>0$

Since we acquired a positive result, g(x) is concave up for x < -4.

For -4 < x < 3, we can use 0. So:

$g^\prime^\prime(0)=(0-3)^2(0+4)(0-6)=-216$

Since we acquired a negative result, g(x) is concave down for -4 < x < 3.

And since the sign changed before and after the possible inflection point at x = -4, x = -4 is indeed an inflection point.

For 3 < x < 6, we can use 4. So:

$g^\prime^\prime(4)=(4-3)^2(4+4)(4-6)=-16$

Since we acquired a negative result, g(x) is concave down for 3 < x < 6.

Since the sign didn't change before and after the possible inflection point at x = 3 (it stayed negative both times), x = -3 is not a inflection point.

And finally, for x > 6, we can use 7. So:

$g^\prime^\prime(7)=(7-3)^2(7+4)(7-6)=176>0$

So, g(x) is concave up for x > 6.

And since we changed signs before and after the inflection point at x = 6, x = 6 is indeed an inflection point.

3 0

3 years ago

Is 7/8 smaller than 3/4

Kay [80]

As decimals lets look at them:)
7/8 = 0.875
3/4 = 0.75

In this case 7/8 is actually bigger.

love, the Pineapple.
<3

6 0

4 years ago

Read 2 more answers

Tammy drove 715 miles in 11 hours. at the same rate, how long would it take her to drive 845 miles?

Alex787 [66]

Answer:

Step-by-step explanation:

So we have direct proportions here.

So

715=11

845=x

845*11/715

x=13

To check our work.

715/11=65

65*13=845.

Basically, in this formula, you use cross multiplication. So A*B=B*A. B and B go together and A and A go together/

So we can use the formula x = b*b/a. Since A is one of the A's and the other value of A is missing, we can use this formula to find it.

Hope this helped, ask me if you have any questions.

8 0

3 years ago