Write the following quotient in the form a+bi. -7i/2-7i

Mathematics

2 answers:

Helga [31]3 years ago

8 0

Answer:

$\large\boxed{\dfrac{49}{53}-\dfrac{14}{53}i}$

Step-by-step explanation:

$\text{Use}\\\\i=\sqrt{-1}\to i^2=-1\\\\(a-b)(a+b)=a^2-b^2\to(a-bi)(a+bi)=a^2+b^2\\\\\text{distributive property}\ a(b+c)=ab+ac\\---------------------\\\\\dfrac{-7i}{2-7i}=\dfrac{-7i}{2-7i}\cdot\dfrac{2+7i}{2+7i}=\dfrac{-7i(2+7i)}{2^2+7^2}=\dfrac{(-7i)(2)+(-7i)(7i)}{4+49}\\\\=\dfrac{-14i-49i^2}{53}=\dfrac{-14i-49(-1)}{53}=\dfrac{-14i+49}{53}\\\\=\dfrac{49}{53}-\dfrac{14}{53}i$

Illusion [34]3 years ago

3 0

Answer:

Write the following quotient in the form a+bi.

-7i/2-7i

Step-by-step explanation:

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A cake has circumference of 25 1/7 inches. What is the area of the cake? Use 22/7 to approximate π. Round to the nearest hundred

choli [55]

Answer:

50.29 in^2

Step-by-step explanation:

From the circumference we need to find the radius.

Since C = 2*pi*r, r = C / (2*pi).

Here, with C = 25 1/7 in, r = (25 1/7 in) / [ 2(22/7) ], or r = 4 in

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5 0

3 years ago

A local company makes a candy that is supposed to weigh 1.00 ounces. A random sample of 25 pieces of candy produces a mean of 0.

AysviL [449]

Answer:

$n=(\frac{2.58(0.004)}{0.001})^2 =106.50 \approx 107$

So the answer for this case would be n=107 rounded up to the nearest integer

Step-by-step explanation:

Information given

$\bar X= 0.996$ the sample mean

$s=0.004$ the sample deviation

$n =25$ the sample size

Solution to the problem

The margin of error is given by this formula:

$ME=z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (a)

And on this case we have that ME =0.001 and we are interested in order to find the value of n, if we solve n from equation (a) we got:

$n=(\frac{z_{\alpha/2} \sigma}{ME})^2$ (b)

We can use as estimator of the real population deviation the sample deviation for this case $\hat \sigma = s$ / The critical value for 99% of confidence interval is given by $z_{\alpha/2}=2.58$ , replacing into formula (b) we got: