Find the perimeter of 8cm, 5cm, 7cm, 10cm

Let u = (1, 2 -2), v= (2, 1, 3) and w = j + 4k. a) Find cos theta, where theta is the angle in degrees between u and w.

vodka [1.7K]

Answer: The value of cos theta is -0.352.

Step-by-step explanation:

Since we have given that

$\vec{u}=1\hat{i}+2\hat{j}-2\hat{k}\and\\\\\vec{w}=\hat{j}+4\hat{k}$

We need to find the cos theta between u and w.

As we know the formula for angle between two vectors.

$\cos\ \theta=\dfrac{\vec{u}.\vec{w}}{\mid u\mid \mid w\mid}$

So, it becomes,

$\cos \theta=\dfrac{2-8}{\sqrt{1^2+2^2+(-2)^2}\sqrt{1^2+4^2}}\\\\\cos \theta=\dfrac{-6}{\sqrt{17}\sqrt{17}}=\dfrac{-6}{17}=-0.352\\\\\theta=\cos^{-1}(\dfrac{-6}{17})=110.66^\circ$

Hence, the value of cos theta is -0.352.

8 0

3 years ago

What is the first step in evaluating the expression shown below? (12.9-3.1) 6.2-2 + 43

Nata [24]

Answer:

Subtract 3.1 from 12.9

Hope it helped

3 0

2 years ago

Solve the following pair of equations simultaneously.

Alchen [17]

Answer:

No solutions.

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS
Equality Properties

Algebra I

Solving systems of equations using substitution/elimination
Solving systems of equations by graphing
Expanding
Finding roots of a quadratic
Standard Form: ax² + bx + c = 0
Quadratic Formula: $x=\frac{-b\pm\sqrt{b^2-4ac} }{2a}$

Step-by-step explanation:

Step 1: Define systems

2x - y = 9

4x² + 3y² - 2x + y = 16

Step 2: Rewrite systems

2x - y = 9

Subtract 2x on both sides: -y = 9 - 2x
Divide -1 on both sides: y = 2x - 9

Step 3: Redefine systems

y = 2x - 9

4x² + 3y² - 2x + y = 16

Step 4: Solve for x

Substitution

Substitute in y: 4x² + 3(2x - 9)² - 2x + (2x - 9) = 16
Expand: 4x² + 3(4x² - 36x + 81) - 2x + (2x - 9) = 16
Distribute 3: 4x² + 12x² - 108x + 243 - 2x + 2x - 9 = 16
Combine like terms: 16x² - 108x + 234 = 16
Factor GCF: 2(8x² - 54x + 117) = 16
Divide 2 on both sides: 8x² - 54x + 117 = 8
Subtract 8 on both sides: 8x² - 54x + 109 = 0
Define variables: a = 8, b = -54, c = 109
Resubstitute: $x=\frac{54\pm\sqrt{(-54)^2-4(8)(109)} }{2(8)}$
Exponents: $x=\frac{54\pm\sqrt{2916-4(8)(109)} }{2(8)}$
Multiply: $x=\frac{54\pm\sqrt{2916-3488} }{16}$
Subtract: $x=\frac{54\pm\sqrt{-572} }{16}$

Here we see that we start to delve into imaginary roots. Since on a real number plane, we do not have imaginary roots, there would be no solution to the systems of equations.

Step 5: Graph systems

We can verify our results.

8 0

3 years ago

The cost, C, of producing x-bikes is given by C = 22x +132 . The revenue gained from selling x-bikes is given by R=350x. Ifthepr

Butoxors [25]

Answer:

I think its B

Step-by-step explanation:

5 0

3 years ago

What do opposites on a number line equal?

GREYUIT [131]

The opposite on number line means is that the value of one number will be opposite to that. For example, there is number 4 on the number line, the opposite number of it will be -4. Furthermore, if there is -5 the opposite of it will be 5. Hope it help!

7 0

3 years ago