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1 year ago

Find, correct to the nearest degree, the three angles of the triangle with the vertices d(0,1,1), e( 2, 4,3) − , and f(1, 2, 1)

1 answer:

8 0

Well, here's one way to do it at least...

For reference, let 'a' be the side opposite A (segment BC), 'b' be the side opposite B (segment AC) and 'c' be the side opposite C (segment AB). 

Let P=(4,0) be the projection of B onto the x-axis. 
Let Q=(-3,0) be the projection of C onto the x-axis. 

Look at the angle QAC. It has tangent = 5/4 (do you see why?), so angle A is atan(5/4). 

Likewise, angle PAB has tangent = 6/3 = 2, so angle PAB is atan(2). 

Angle A, then, is 180 - atan(5/4) - atan(2) = 65.225. One down, two to go. 

||b|| = sqrt(41) (use Pythagorian Theorum on triangle AQC) 
||c|| = sqrt(45) (use Pythagorian Theorum on triangle APB) 

Using the Law of Cosines... 
||a||^2 = ||b||^2 + ||c||^2 - 2(||b||)(||c||)cos(A) 
||a||^2 = 41 + 45 - 2(sqrt(41))(sqrt(45))(.4191) 
||a||^2 = 86 - 36 
||a||^2 = 50 
||a|| = sqrt(50) 

Now apply the Law of Sines to find the other two angles. 

||b|| / sin(B) = ||a|| / sin(A) 
sqrt(41) / sin(B) = sqrt(50) / .9080 
(.9080)sqrt(41) / sqrt(50) = sin(B) 
.8222 = sin(B) 
asin(.8222) = B 
55.305 = B 

Two down, one to go... 

||c|| / sin(C) = ||a|| / sin(A) 
sqrt(45) / sin(C) = sqrt(50) / .9080 
(.9080)sqrt(45) / sqrt(50) = sin(C) 
.8614 = sin(C) 
asin(.8614) = C 
59.470 = C 

So your three angles are: 

A = 65.225 
B = 55.305 
C = 59.470

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Write the equation of a line that is perpendicular to y = 5 y=5y, equals, 5 and that passes through the point ( − 7 , − 5 ) (−7,

Jlenok [28]

The line of the equation perpendicular to y=5 and cuts through (-5,-7) will be given by
m(x-x1)=y-y1
where m=slope.
from y=0x+5, the slope of the perpendicular line m=0,
thus the equation will be:
0(x--5)=y--7
0=y+7
y=-7
The equation is y=-7

3 0

1 year ago

Read 2 more answers

se the function to show that fx(0, 0) and fy(0, 0) both exist, but that f is not differentiable at (0, 0). f(x, y) = 9x2y x4 + y

alexandr1967 [171]

Answer:

It is proved that $f_x, f_y$ exixts at (0,0) but not differentiable there.

Step-by-step explanation:

Given function is,

$f(x,y)=\frac{9x^2y}{x^4+y^2}; (x,y)\neq (0,0)$

To show exixtance of $f_x(0,0), f_y(0,0)$ we take,

$f_x(0,0)=\lim_{h\to 0}\frac{f(h+0,k+0)-f(0,0)}{h}=\lim_{h\to 0}\frac{\frac{9h^2k}{h^4+k^2}-0}{h}\\\therefore f_x(0,0)=\lim_{h\to 0}\frac{9hk}{h^4+k^2}=\lim_{h\to 0}\frac{9k}{h^3+\frac{k^2}{h}}=0$ exists.

And,

$f_y(0,0)=\lim_{k\to 0}\frac{f(h,k)-f(0,0)}{k}=\lim_{k\to 0}\frac{9h^2k}{k(h^4+k^2)}=\lim_{k\to 0}\frac{9h^2}{h^4+k^2}=\frac{9}{h^2}$ exists.

To show f(x,y) is not differentiable at the origin cheaking continuity at origin be such that,

$\lim_{(x,y)\to (0,0)}\frac{9x^2y}{x^4+y^2}=\lim_{x\to 0\\ y=mx^2}\frac{9x^2y}{x^4+y^2}=\frac{9x^2\times m x^2}{x^4+m^2x^4}=\frac{9m}{1+m^2}$ where m is a variable.

which depends on various values of m, therefore limit does not exists. So f(x,y) is not continuous at (0,0). Hence it is not differentiable at (0,0).

4 0

2 years ago

At the We-Pack Shipping, the workers can unload 28 trucks in 7 hours. Which of the following is a correct unit rate for this sit

Over [174]

28 trucks/7 hours=4 trucks/1 hour.
Therefore A.) and B.) are incorrect.
The wording of these last two answers confusesme but I believe the correct one is D.) because 1 hour (per-/) 4 trucks.

Hope this helps!

7 0

1 year ago

Read 2 more answers

El Sr negron tiene que redactar una serie de cartas en su oficina. A Lourdes le toma 6 horas pasar todas las cartas. A su compañ

vodka [1.7K]

El Sr negron tiene que redactar una serie de cartas en su oficina. A Lourdes le toma 6 horas pasar todas las cartas. A su compañera rosabel, le toma 9 horas en realizar la misma tarea. Si ambas trabajan juntas para hacer todo el trabajo d ela oficina,

a. Cuánto tiempo le tomará a ambas realizar el trabajo?

Answer:

3.6 horas

Step-by-step explanation:

Sea el número total de horas que ambos trabajaron = T

Deje que la cantidad total de letras por las que pasaron = 1

De la pregunta, se nos dice:

Lourdes necesitó 6 horas para revisar las cartas.

Esto significa que, cada 1 hora, Lourdes revisaba 1/6 de las letras

Rosabel tardó 9 horas en leer las letras.

Esto significa que, cada 1 hora, Rosabel revisó 1/9 de las letras

Por lo tanto,

(1/6 × 1) T + (1/9 × 1) T = 1

(1/6 + 1/9) T = 1

(3 + 2/18) T = 1

(18/5) T = 1

5T / 18 = 1

Cruz multiplicar

5T = 18

T = 18/5

T = 3.6 horas

Por lo tanto, les tomó a ambas 3.6 horas hacer el trabajo.

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2 years ago

A human resources manager keeps a record of how many years each employee at a large company has been working in their current ro

REY [17]

Answer:

0.3085 = 30.85% probability that the mean years of experience from the sample of 4 is greater than 3.5 years.

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal probability distribution

When the distribution is normal, we use the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

Central Limit Theorem

The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$ .

For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean $\mu = p$ and standard deviation $s = \sqrt{\frac{p(1-p)}{n}}$