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3 years ago

Verify that: cos(x+y)cos(x-y)=cos^2x-sin^2y

1 answer:

4 0

COS(X+Y)COS(X-Y)
=(COSX*COSY-SINX*SINY)(COSX*COSY+SINX*SINY)
=(COSX*COSY)^2-(SINX*SINY)^2
=COS^2 X(1-SIN^2 Y)-(1-COS^2 X)SIN^2 Y
=COS^2 X -COS^2 X*SIN^2 Y-SIN^2 Y +COS^2 X SIN^2 Y
<span>=COS^2X-SIN^2Y</span>

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What is the answer to, -2x - 13 = -3x - 5

shtirl [24]

-2x - 13 = -3x - 5

Step 1: Combine like terms

x's go with x's (-2x and -3x). To do this add 2x to both sides

(-2x + 2x) - 13 = (-3x + 2x) - 5

(0) - 13 = (-x) - 5

- 13 = -x - 5

normal numbers go with normal numbers ( -13 and -5). To do this add 5 to both sides

(- 13 + 5) = -x + (- 5 + 5)

-8 = -x + (0)

-8 = -x

Step 2: Isolate x by dividing -1 to both sides (this will take the negative sign away from the x)

$\frac{-8}{-1} =\frac{-x}{-1}$

8 = x

x= 8

Hope this helped!

6 0

3 years ago

Select the correct answer

motikmotik

Answer:

Step-by-step explanation:

80%=4/5

4/5 of 20 is 4

They lose 4 matches.

5 0

3 years ago

Help<br> Pls it’s due in 1 hour!

ohaa [14]

Answer:

Step-by-step explanation:

4 0

3 years ago

Lindsey found a cupcake and weighed it on a digital scale. The cupcake weight 0.35 lb. what is the weight of the Rock in expande

SVEN [57.7K]

The weight of the cupcake in an expanded form is 3.5 * 10⁻¹ lb

<h3>How to determine the weight?</h3>

The weight is given as:

Weight = 0.35 lb

Remove the unit

Weight = 0.35

Multiply the weight by 1

Weight = 0.35 * 1

Express 1 as 10/10

Weight = 0.35 * 10/10

Evaluate the product

Weight = 3.5 * 1/10

Express 1/10 as an exponent

Weight = 3.5 * 10⁻¹

Return the unit

Weight = 3.5 * 10⁻¹ lb

Hence, the weight in expanded form is 3.5 * 10⁻¹ lb