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4 years ago

Factor the trigonometric equation. cos2x-cosx

Mathematics

1 answer:

prisoha [69]4 years ago

4 0

Cos(2x) = cos^2(x) - sin^2(x) - cos(x)

but sin^2(x) = 1 - cos^2(x)

cos(2x) - cos(x) = cos^2(x) - (1 - cos^2(x) ) - cos(x)

cos(2x) - cos(x) = cos^2(x) - 1 + cos^2(x) - cos(x)

cos(2x) - cos(x) = 2cos^2(x) - 1 - cos(x)

cos(2x) - cos(x) = (2cos(x) + 1)(cos(x) - 1)

I think this is what you have asked for.

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In 25 words or fewer, is this solution reasonable? Why or why not?

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3 years ago

The bus is scheduled to leave at 16:24pm. It doesn't actually leave until 7 minutes later. You

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Step-by-step explanation:

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3 years ago

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in a school election 1/3 of the students vote. there are 655 ballots. find the number of students at the school

Basile [38]

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Step-by-step explanation:

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3 years ago

I need help on questions 48 49 and 50 and u need to find the surface area of the 3 polyhedras please and thank you!

White raven [17]

48. The surface area of a cylinder is given by

... A = 2πr² + 2πrh = 2πr(r+h)

For r = 13 mi and h = 7 mi, this becomes

... A = 2π(13 mi)(13 mi + 7 mi) = 520π mi²

The surface area of the cylinder is 520π mi² ≈ 1634 mi².

49. The surface area of a rectangular prism is

... A = 2(LW + H(L+W))

For L = 20 m, W = 10 m, H = 7 m, this becomes

... A = 2((20 m)(10 m) + (7 m)(20 m + 10 m)) = 2(200 m² + 210 m²) = 820 m²

The surface area of the prism is 820 m².

50. The formula is the same as for problem 48.

For r = 10 m and h = 13 m, this becomes

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The surface area of the cylinder is 460π m² ≈ 1445 m².

_____

When calculations are repetitive, it is convenient to let a calculator or spreadsheet do them.

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4 years ago

-2x + y =0 5x + 3y = -11

Ivahew [28]

Answer:

(-1, -2)

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right

Equality Properties

Algebra I

Solving systems of equations using substitution/elimination
Solving systems of equations by graphing

Step-by-step explanation:

Step 1: Define Systems

-2x + y = 0

5x + 3y = -11

Step 2: Rewrite Systems

-2x + y = 0

Add 2x on both sides: y = 2x

Step 3: Redefine Systems

y = 2x

5x + 3y = -11

Step 4: Solve for x

Substitution

Substitute in y: 5x + 3(2x) = -11
Multiply: 5x + 6x = -11
Combine like terms: 11x = -11
Isolate x: x = -1

Step 5: Solve for y

Define equation: y = 2x
Substitute in x: y = 2(-1)
Multiply: y = -2

Step 6: Graph Systems

Check the solution set.

3 0

3 years ago