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1 year ago

Prove that cos^4∆ - sin^4∆ = 2cos^2∆ - 1

1 answer:

3 0

$\cos^{4} x-\sin^{4} x\\\\=(\cos^{2} x+\sin^{2} x)(\cos^{2} x-\sin^{2} x)\\\\=\cos^{2} x-\sin^{2} x\\\\=\cos^{2} x-(1-\cos^{2} x)\\\\=2\cos^{2} x-1$

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What is the slope of the line that passes through the points: (5, -3) and (-1,6)

elena55 [62]

Answer:

-1/2

Step-by-step explanation:

https://www.calculator.net/slope-calculator.html

That website has the best explanation ^^^^^

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2 years ago

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Tony is planning to buy a house. He needs to borrow $565,000 from the bank for 30 yrs at an APR of 3.2%. What will his monthly p

HACTEHA [7]

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2 years ago

which ordered pairs in the form (x, y) are solutions to the equation 3x−4y=21 ? Select each correct answer. (−1, −6) (−3, 3) (11

Valentin [98]

Answer:

see explanation

Step-by-step explanation:

To determine which ordered pairs are solutions to the equation

Substitute the x and y values into the left side of the equation and if equal to the right side then they are a solution.

(- 1, - 6)

3(- 1) - 4(- 6) = - 3 + 24 = 21 = right side ← thus a solution

(- 3, 3)

3(- 3) - 4(3) = - 9 - 12 = - 21 ≠ 21 ← not a solution

(11, 3)

3(11) - 4(3) = 33 - 12 = 21 = right side ← thus a solution

(7, 0)

3(7) - 4(0) = 21 - 0 = 21 = right side ← thus a solution

The ordered pairs (- 1, - 6), (11, 3), (7, 0) are solutions to the equation

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3 years ago

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What is the value of y in this system of equations: 3x + y = 9 y = –4x + 10 ?

Ahat [919]

3x + y = 9 (I)
y = –4x + 10 (II)
------------------------
 $\left \{ {{3x + y = 9 } \atop {y = -4x + 10 }} \right.$

Pass the incognito "4x" to the first term, changing the signal when changing sides.
-------------------------
simplify by (-1)
 $\left \{ {{3x + y = 9.(-1)} \atop {4x + y = 10 }} \right.$ 

-------------------------
 $\left \{ {{- 3x - \diagup\!\!\!\!y =-9} \atop {4x + \diagup\!\!\!\!y = 10}} \right. 
$

-------------------------
 $\left \{ {{- 3x = - 9} \atop {4x = 10}} \right.$ 

-----------
 $\boxed{x = 1}$ 

Substitute in equation (I) to find the value of "Y".

3x + y = 9 (I)
3*(1) + y = 9
3 + y = 9
y = 9 - 3
$\boxed{y = 6}$

Answer:
$\boxed{\boxed{ \left \ {{x=1} \atop {y=6}} \right. }}$

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3 years ago

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Lilit [14]

Answer:

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Step-by-step explanation:

1: Move 3.452 to the end of the equation

(3.452 × 100) -> (3.452 × 100 = 3.452)

2: Since 100 has 2 zeros, move the decimal point 2 places to the right.

(3.452 × 100 = 3.452) -> (345.2)

Hope this helps!

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3 years ago

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