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3 years ago

How do you right 7 to the -2 power as a simple fraction

Mathematics

1 answer:

tatuchka [14]3 years ago

7 0

Answer:

1/49

Step-by-step explanation:

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Show that cos(3x) = cos3(x) − 3 sin2(x)cos(x). (Hint: Use cos(2x) = cos2(x) − sin2(x) and the cosine sum

otez555 [7]

Step-by-step explanation:

To prove:

$\cos 3x=\cos^3x-3\sin^2 x\cos x$

Identities used:

$\cos(A+B)=\cos A\cos B+\sin A\sin B$ ......(1)

$\sin 2A=2\sin A\cos A$ ........(2)

$\cos 2A=\cos^2A-\sin^2 A$ .......(3)

Taking the LHS:

$\Rightarrow \cos 3x=\cos (x+2x)$

Using identity 1:

$\Rightarrow \cos (x+2x)=\cos x\cos 2x-\sin x\sin 2x$

Using identities 2 and 3:

$\Rightarrow \cos x(\cos ^2x-\sin^2 x)-\sin x(2\sin x\cos x)\\\\\Rightarrow \cos^3x-\sin^2x\cos x-2\sin^2 x\cos x\\\\\Rightarrow \cos^3x-3\sin^2x\cos x$

As, LHS = RHS

Hence proved

4 0

2 years ago

<img src="https://tex.z-dn.net/?f=5x%20%5Ctimes%2021%20%3D%207" id="TexFormula1" title="5x \times 21 = 7" alt="5x \times 21 = 7"

pentagon [3]

Answer: Should be X= 1/15

4 0

2 years ago

Perimeter of 316 and 67 m

storchak [24]

Answer:

383 m

Step-by-step explanation:

3 0

3 years ago

Read 2 more answers

What is 1/2 of 25? _______Explain.

Scilla [17]

Answer:

12.5

Step-by-step explanation:

0.5x25=12.5. FILLER

7 0

3 years ago

Select the correct answer.

Sonja [21]

Answer:

B) 5 + 17i is your answer.

Step-by-step explanation:

In order to write this equation as a complex number in standard form, you must first simplify each term.

Apple the distributive property.

21 - 4i - 1 * 16 - (7i) + 28i

Multiply -1 by 16.

21 - 4i -16 - (7i) + 28i

Multiply 7 by -1.

21 - 4i - 16 - 7i + 28i

Now simplify by adding terms :)

Subtract 16 from 21.

5 - 4i - 7i + 28i

Subtract 7i from -4i.

5 - 11i + 28i

Add -11i and 28i.

= 5 + 17i

5 0

2 years ago