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gavmur [86]
3 years ago
12

Please help with this problem.

Mathematics
1 answer:
larisa86 [58]3 years ago
6 0

Answer:

60°, 120°

Step-by-step explanation:

\frac{ {tan}^{2}x }{2}  - 2 {cos}^{2}x = 1 \\   \\  \frac{ {tan}^{2}x  - 4{cos}^{2}x }{2} = 1 \\  \\ {tan}^{2}x  - 4{cos}^{2}x = 2 \\  \\  \frac{{sin}^{2}x}{{cos}^{2}x} - 4{cos}^{2}x = 2 \\  \\ \frac{{sin}^{2}x - 4{cos}^{4}x}{{cos}^{2}x}  = 2 \\  \\ {sin}^{2}x - 4{cos}^{4}x = 2{cos}^{2}x \\  \\ 4{cos}^{4}x  + 2{cos}^{2}x - {sin}^{2}x = 0  \\  \\ 4{cos}^{4}x  + 2{cos}^{2}x  +  {cos}^{2}x  - 1= 0  \\  \\ 4{cos}^{4}x  + 3{cos}^{2}x   - 1= 0  \\  \\ 4{cos}^{4}x  + 4{cos}^{2}x -   {cos}^{2}x - 1= 0  \\  \\4{cos}^{2}x({cos}^{2}x + 1) - 1({cos}^{2}x + 1) = 0 \\  \\ ({cos}^{2}x + 1)(4{cos}^{2}x - 1) = 0 \\  \\ ({cos}^{2}x + 1) = 0 \: or \: (4{cos}^{2}x - 1) = 0 \\  \\ {cos}^{2}x =  - 1 \: or \: 4{cos}^{2}x = 1 \\  \\ {cos}x = \sqrt{ - 1}  \: which \: is \: not \: possible \\  \therefore \: {cos}^{2}x =  \frac{1}{4}  \\  \\ \therefore \: {cos}x =   \pm\frac{1}{2} \\  \\ \therefore \: {cos}x =   \frac{1}{2}  \: or \: {cos}x =    - \frac{1}{2}  \\  \\ \therefore \: {cos}x =   {cos}60 \degree \: or \: {cos}x =     {cos}120 \degree \\  \\ \therefore \:x = 60 \degree \:  \: or  \: \: x  = 120 \degree

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Hope this helps!

4 0
3 years ago
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3 years ago
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Solve for |2x + 4|-1=7
Rudik [331]

Answer:

x = - 6 or x = 2

Step-by-step explanation:

The absolute value function always returns a positive value. However, the expression inside can be positive or negative.

Given

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| 2x + 4 | = 8, thus

2x + 4 = 8 ( subtract 4 from both sides )

2x = 4 ( divide both sides by 2 )

x = 2

OR

-(2x + 4) = 8

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x = - 6

As a check

Substitute these values into the left side of the equation and if equal to the right side then they are the solutions.

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6 0
3 years ago
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Answer:

(-0.5,-2.5)

Step-by-step explanation:

  • (x1 + x2) / 2 = x midpoint
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<h3>X:</h3>

⇒ 2 + -3 = 5

⇒ 5 / 2 = -0.5

<h3>Y:</h3>

⇒ 4 + -9 = -5

⇒ -5 / 2 = -2.5

→ = (-0.5, -2.5)

4 0
3 years ago
Read 2 more answers
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