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Lorico [155]
3 years ago
11

What is the value of (7 + 2i)(3 - i)?

Mathematics
1 answer:
Harrizon [31]3 years ago
7 0
There are two ways to work this out: normal variables or using "imaginary" numbers.

Normal variables:
(7+2i)(3-i)\\(7*3)+[7*(-i)]+(3*2i)+[2i*(-i)]\\21-7i+6i-2i^{2}\\\\21-i-2i^{2}

Imaginary numbers:
Using the result from earlier:
21-i-2i^{2}
Now since i = \sqrt{-1}, then the expression becomes:
21-i-2i^{2}\\21-i-2(\sqrt{-1})^{2}\\21-i+(-2)(-1)\\21-i+2\\\\23-i
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3 years ago
A 150 cm pendulum swings through an arc which measured 100pi cm. In exact radians, through what angle does it swing?
choli [55]

Answer:

Pendulum will swing by an angle 0.666π

Step-by-step explanation:

We have given arc = 100\pi cm

And length of the pendulum l = 150 cm

Length of the pendulum will be equal to radius of the pendulum so r = 150 cm

Arc is given by arc=radius\times angle

So 100\pi =150\times\times  \Theta

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So pendulum will swing by an angle 0.666π

5 0
3 years ago
(ASAP PICTURE ADDED) What is the simplified form of the following expression?
bonufazy [111]

Answer:

option c is correct.

Step-by-step explanation:

7\left(\sqrt[3]{2x}\right)-3\left(\sqrt[3]{16x}\right)-3\left(\sqrt[3]{8x}\right)

WE need to simplify this equation.

Solve the parenthesis of each term.

=7\left\sqrt[3]{2x}\right-3\left\sqrt[3]{16x}\right-3\left\sqrt[3]{8x}\right

Now, We will find factors of the terms inside the square root

factors of 2: 2

factors of 16 : 2x2x2x2

factors of 8: 2x2x2

Putting these values in our equation:=7\left(\sqrt[3]{2x}\right)-3\left(\sqrt[3]{2X2X2X2 x}\right)-3\left(\sqrt[3]{2X2X2 x}\right)\\=7\left(\sqrt[3]{2x}\right)-3\left(\sqrt[3]{2X2X2} \sqrt[3] {2 x}\right)-3\left(\sqrt[3]{2X2X2} \sqrt[3]{x}\right)\\=7\left(\sqrt[3]{2x}\right)-3\left(\sqrt[3]{2^3} \sqrt[3] {2 x}\right)-3\left(\sqrt[3]{2^3} \sqrt[3]{x}\right)\\=7\left(\sqrt[3]{2x}\right)-3*2\left(\sqrt[3] {2 x}\right)-3*2\left(\sqrt[3]{x}\right)\\=7\left(\sqrt[3]{2}\sqrt[3]{x}\right)-6\left(\sqrt[3] {2}\sqrt[3]{x})-6\left(\sqrt[3]{x}\right)

Adding like terms we get:

=7\left(\sqrt[3]{2}\sqrt[3]{x}\right)-6\left(\sqrt[3] {2}\sqrt[3]{x})-6\left(\sqrt[3]{x}\right\\=(\sqrt[3] {2}\sqrt[3]{x})-6\left(\sqrt[3]{x}\right)\\

(\sqrt[3] {2}\sqrt[3]{x})-6\left(\sqrt[3]{x}\right)\\can\,\,be \,\, written\,\, as\,\,\\(\sqrt[3] {2x})-6\left(\sqrt[3]{x}\right)

So, option c is correct

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