What does x mean in a math equation

Mathematics

2 answers:

lara [203]3 years ago

8 0

X is a variable. You dont have to know what the value is.In the equation it may ask you to find the value of x

monitta3 years ago

4 0

An unknown variable ..............

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Find the missing measure <br><br><br> ; Help me understand how to solve this.

blsea [12.9K]

Use Soh Cah Toa. Soh(sin) is the Opposite side divided by the Hypotenuse side so in this case 21/20. Since we need the angle here we would use the inverse of sin. Your equation is Sin(x)=Opposite/Hypotenuse=21/20=1.05
Now solve sin(x)=1.05
Re-arange into
X=sin^-1 (1.05) but since you can’t have a inverse sin of a number more than one it is inconclusive or no answer

8 0

3 years ago

Suppose that diameters of a new species of apple have a bell-shaped distribution with a mean of 7.43cm and a standard deviation

malfutka [58]

Answer:

Approximately 68% of the apples have diameters that are between 7.08cm and 7.78cm.

Step-by-step explanation:

The Empirical Rule states that, for a normally distributed random variable:

Approximately 68% of the measures are within 1 standard deviation of the mean.

Approximately 95% of the measures are within 2 standard deviations of the mean.

Approximately 99.7% of the measures are within 3 standard deviations of the mean.

In this problem, we have that:

Mean of 7.43cm, standard deviation of 0.35cm.

What percentage of the apples have diameters that are between 7.08cm and 7.78cm?

7.43 - 0.35 = 7.08 cm.

7.43 + 0.35 = 7.778 cm.

Within 1 standard deviation of the mean, so approximately 68% of the apples have diameters that are between 7.08cm and 7.78cm.

5 0

3 years ago

suppose X and Y are independent random variables, both with normal distributions. If X has a mean of 45 with a standard deviatio

djyliett [7]

Answer:

0.9772 = 97.72% probability that a randomly generated value of X is greater than a randomly generated value of Y

Step-by-step explanation:

When the distribution is normal, we use the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

In this question:

$\mu_X = 45, \sigma_X = 4, \mu_Y = 35, \sigma_Y = 3$

What is the probability that a randomly generated value of X is greater than a randomly generated value of Y

This means that the subtraction of X by Y has to be positive.

When we subtract two normal variables, the mean is the subtraction of their means, and the standard deviation is the square root of the sum of their variances. So

$\mu = \mu_X - \mu_Y = 45 - 35 = 0$