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2 years ago

6

PLS HELP!! A student randomly guesses the answers to two true-false questions. Describe and correct the error in finding the pro

bability of the student guessing both answers correctly. The student can either guess two incorrect answers, two correct answers, or one of each. So the probability of guessing both answers correctly is 1/3

1 answer:

Nitella [24]2 years ago

6 0

Answer:

The student was wrong. The probability is actually 1/4.

Step-by-step explanation:

Let's say you have question A and question B. You could have incorrect on A, and incorrect on B. Or, you could have incorrect on A, but a correct on B. Or, you could have an incorrect on B, but a correct on A. Or, both could be correct. <em><u>Since there are 4 different possibilities, the actual probability is 1/4.</u></em>

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Change each of the following points from rectangular coordinates to spherical coordinates and to cylindrical coordinates.

FromTheMoon [43]

Answer and Step-by-step explanation: Spherical coordinate describes a location of a point in space: one distance (ρ) and two angles (Ф,θ).To transform cartesian coordinates into spherical coordinates:

$\rho = \sqrt{x^{2}+y^{2}+z^{2}}$

$\phi = cos^{-1}\frac{z}{\rho}$

For angle θ:

If x > 0 and y > 0: $\theta = tan^{-1}\frac{y}{x}$ ;

If x < 0: $\theta = \pi + tan^{-1}\frac{y}{x}$ ;
If x > 0 and y < 0: $\theta = 2\pi + tan^{-1}\frac{y}{x}$ ;

Calculating:

a) (4,2,-4)

$\rho = \sqrt{4^{2}+2^{2}+(-4)^{2}}$ = 6

$\phi = cos^{-1}(\frac{-4}{6})$

$\phi = cos^{-1}(\frac{-2}{3})$

For θ, choose 1st option:

$\theta = tan^{-1}(\frac{2}{4})$

$\theta = tan^{-1}(\frac{1}{2})$

b) (0,8,15)

$\rho = \sqrt{0^{2}+8^{2}+(15)^{2}}$ = 17

$\phi = cos^{-1}(\frac{15}{17})$

$\theta = tan^{-1}\frac{y}{x}$

The angle θ gives a tangent that doesn't exist. Analysing table of sine, cosine and tangent: θ = $\frac{\pi}{2}$

c) (√2,1,1)

$\rho = \sqrt{(\sqrt{2} )^{2}+1^{2}+1^{2}}$ = 2

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

$\phi$ = $\frac{\pi}{3}$

$\theta = tan^{-1}\frac{1}{\sqrt{2} }$

d) (−2√3,−2,3)

$\rho = \sqrt{(-2\sqrt{3} )^{2}+(-2)^{2}+3^{2}}$ = 5

$\phi = cos^{-1}(\frac{3}{5})$

Since x < 0, use 2nd option:

$\theta = \pi + tan^{-1}\frac{1}{\sqrt{3} }$

$\theta = \pi + \frac{\pi}{6}$

$\theta = \frac{7\pi}{6}$

Cilindrical coordinate describes a 3 dimension space: 2 distances (r and z) and 1 angle (θ). To express cartesian coordinates into cilindrical:

$r=\sqrt{x^{2}+y^{2}}$

Angle θ is the same as spherical coordinate;

z = z

Calculating:

a) (4,2,-4)

$r=\sqrt{4^{2}+2^{2}}$ = $\sqrt{20}$

$\theta = tan^{-1}\frac{1}{2}$

z = -4

b) (0, 8, 15)

$r=\sqrt{0^{2}+8^{2}}$ = 8

$\theta = \frac{\pi}{2}$

z = 15

c) (√2,1,1)

$r=\sqrt{(\sqrt{2} )^{2}+1^{2}}$ = $\sqrt{3}$

$\theta = \frac{\pi}{3}$

z = 1

d) (−2√3,−2,3)

$r=\sqrt{(-2\sqrt{3} )^{2}+(-2)^{2}}$ = 4

$\theta = \frac{7\pi}{6}$

z = 3

5 0

2 years ago

I need someone to help me make these equations!

Sauron [17]

''Two one-step equationsx + 7 = 10x = 7-7 = 10 - 7x = 3
y + 47 = 20y = 47 - 47 = 20 - 47y = 27
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+ 12 + 7 = 1919/20 =

Distributive property2x - 4(+4) = 10(+4)2x - 16 = 402x - 16 + 16 = 40 + 162x = 5656 ÷ 2 = 28x = 28
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hope this helps

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2 years ago

Bobby is 12 years old. His age is nine

KatRina [158]

Answer:

65 because 12 plus 9 is 21 then 3 times 21 is 65

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2 years ago

Edgar is scuba diving 50 feet below the water. He is swimming to the surface at a rate of 3 feet per second. Write an equation t

Y_Kistochka [10]

Answer:

i know the answer but not the equation

Step-by-step explanation:

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2 years ago

What is the answer of K < -5 ?

alexira [117]

To your question, "K<-5", that is the answer. So the answer is K<-5

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3 years ago