Which answer is it for it to be simplified completely?

MATH HELP PLZ!!!

RoseWind [281]

Answer:

a) $tan (157.5) = \frac{1-cos 315}{sin315}$

b)

$sin (165) =\sqrt{ \frac{1-cos (330) }{2}}$

c)

$sin^{2} (157.5) = \frac{1-cos (315) }{2}$

d)

cos 330° = 1- 2 sin² (165°)

Step-by-step explanation:

Step(i):-

By using trigonometry formulas

a)

cos2∝ = 2 cos² ∝-1

cos∝ = 2 cos² ∝/2 -1

1+ cos∝ = 2 cos² ∝/2

$cos^{2} (\frac{\alpha }{2}) = \frac{1+cos\alpha }{2}$

b)

cos2∝ = 1- 2 sin² ∝

cos∝ = 1- 2 sin² ∝/2

$sin^{2} (\frac{\alpha }{2}) = \frac{1-cos\alpha }{2}$

Step(i):-

Given

$tan\alpha = \frac{sin\alpha }{cos\alpha }$

we know that trigonometry formulas

$sin\alpha = 2sin(\frac{\alpha }{2} )cos(\frac{\alpha }{2} )$

1- cos∝ = 2 sin² ∝/2

Given

$tan(\frac{\alpha }{2} ) = \frac{sin(\frac{\alpha }{2} )}{cos(\frac{\alpha }{2}) }$

put ∝ = 315

$tan(\frac{315}{2} ) = \frac{sin(\frac{315 }{2} )}{cos(\frac{315 }{2}) }$

multiply with ' 2 sin (∝/2) both numerator and denominator

$tan (\frac{315}{2} )= \frac{2sin^{2}(\frac{315)}{2} }{2sin(\frac{315}{2} cos(\frac{315}{2}) }$

Apply formulas

$sin\alpha = 2sin(\frac{\alpha }{2} )cos(\frac{\alpha }{2} )$

1- cos∝ = 2 sin² ∝/2

now we get

$tan (157.5) = \frac{1-cos 315}{sin315}$

b)

$sin^{2} (\frac{\alpha }{2}) = \frac{1-cos\alpha }{2}$

put ∝ = 330° above formula

$sin^{2} (\frac{330 }{2}) = \frac{1-cos (330) }{2}$

$sin^{2} (165) = \frac{1-cos (330) }{2}$

$sin (165) =\sqrt{ \frac{1-cos (330) }{2}}$

c )

$sin^{2} (\frac{\alpha }{2}) = \frac{1-cos\alpha }{2}$

put ∝ = 315° above formula

$sin^{2} (\frac{315 }{2}) = \frac{1-cos (315) }{2}$

$sin^{2} (157.5) = \frac{1-cos (315) }{2}$

d)

cos∝ = 1- 2 sin² ∝/2

put ∝ = 330°

$cos 330 = 1 - 2sin^{2} (\frac{330}{2} )$

cos 330° = 1- 2 sin² (165°)

3 0

3 years ago

A total of 20 quarters and nickels add up to $4.00. How many nickels are there?

mariarad [96]

Answer:

5 nickels

Step-by-step explanation:

You can setup and solve a system of equations, or you can solve by trial and error until you get the correct answer.

Here is the solution by trial and error.

If all 20 coins are quarters, the value is 20 * $0.25 = $5

That is too much value.

Let's try 16 quarters. 16 quarters are worth 16 * $0.25 = $4.

That is the correct value, but it is only with quarters, and only 16 of them.

We need fewer quarters than 16.

Try 12 quarters: 12 * $0.25 = $3.00

The number of nickels is: 20 - 12 = 8

8 nickels are worth 8 * $0.05 = $0.40

12 quarters and 8 nickels are worth $3.00 + $0.40 = $3.40

There are 20 coins, but the value is too low.

The number of quarters is between 12 and 16.

Try 14 quarters and 6 nickels:

14 * $0.25 + 6 * $0.05 = $3.50 + $0.30 = $3.80

We are closer to $4 but not there yet.

Try 15 quarters and 5 nickels.

15 * $0.25 + 5 * $0.05 = $3.75 + $0.25 = $4

The total value is $4 and there are 20 coins. This is the answer.

15 quarters and 5 nickels works.

Answer: 5 nickels

8 0

3 years ago

The height of adult males on a given South Pacific Island is approximately normally distributed with mean 65 inches and standard

zvonat [6]

Answer:

a) 0.59871

b) 0.22663

e) 0.95994

Step-by-step explanation:

The height of adult males on a given South Pacific Island is approximately normally distributed with mean 65 inches and standard deviation of 4 inches.

We solve using z score

z = (x-μ)/σ, where

x is the raw score

μ is the population mean = 65 inches

σ is the population standard deviation = 4 inches

a). Taller than 64 inches

This means x > 64

Hence,

64 - 65/4

=- 1/4 = -0.25

P-value from Z-Table:

P(x<64) = 0.40129

P(x>64) = 1 - P(x<64) = 0.59871

b.) shorter than 62 inches

Hence,

62 - 65/4

=- 3/4 =- 0.75

P-value from Z-Table:

P(x<62) = 0.22663

c.) between 64 inches and 68 inches

Hence,

for 64 inches

64 - 65/4

=- 1/4 = -0.25

P-value from Z-Table:

P(x = 64) = 0.40129

For 68 inches

Hence,

68 - 65/4

= 3/4= 0.75

P-value from Z-Table:

P(x = 68) = 0.77337

d.) between 58 and 68 inches

e.) taller than 58 inches

Hence,

58 - 65/4

= -6/4 = -1.5

P-value from Z-Table:

P(x<58) = 0.040059

P(x>58) = 1 - P(x<58) = 0.95994

7 0

3 years ago

Graph y = -2x + 5.

antoniya [11.8K]

Answer:

Step-by-step explanation:

6 0

3 years ago

Read 2 more answers

For which equation is x=5 a solution? Help me please ty :)

VladimirAG [237]

Answer:

B)3x=15

Step-by-step explanation:

3x=15

x=15/3

x=5 (proven)

8 0

3 years ago