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ivanzaharov [21]
3 years ago
14

Identify the error or errors in this argument that supposedly shows that if ∃xp (x) ∧ ∃xq(x) is true then ∃x(p (x) ∧ q(x)) is tr

ue. 1. ∃xp (x) ∨ ∃xq(x) premise 2. ∃xp (x) simplification from (1) 3. p (c) existential instantiation from (2) 4. ∃xq(x) simplification from (1) 5. q(c) existential instantiation from (4) 6. p (c) ∧ q(c) conjunction from (3) and (5) 7. ∃x(p (x) ∧ q(x)) existential generalization
Mathematics
1 answer:
Ymorist [56]3 years ago
8 0

The mistake lies in steps 3 and 5.

In fact, you know that there exists some element that satisfies p(x), and some element that satisfies q(x), but you can't assume that the same element satisfies p(x) and q(x) at the same time.

So, you are only allowed to say

p(c) existential instantiation from (2)

q(d) existential instantiation from (4)

and so you can't do the conjunction in step 6 anymore.


Here's an example: if you follow this logic, you would say something like:

"There exists a person who is born in Italy and there exists a person who is born in the USA. Therefore, there exists a person who is born in both Italy and the USA"

which is clearly false: altought there exists a person for each proposition, they are not the same person.


This is even easier if q is the negation of p:

"There exists a number greater than 10, and there exists a number lesser than 10. Therefore, there exists a number that is greater than and lesser than 10 at the same time"

which is clearly absurd

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Answer:

There are less than 5 1/2 cups of sugar.

Step-by-step explanation:

E D G E N U I T Y

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3 years ago
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Easy math please help
insens350 [35]

1) False

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2) B and D

Adjacent angles are those that are directly next to each other and share a common side.

3) C

Angles 1 and 2 are congruent. Angles 3 and 4 are congruent. Both of these pairs have angles that are opposite each other.

4) B

Angles 1 and 2 add up to 180. Angles 3 and 4 add up to 180. Both of these pairs of angles are supplementary.

5) A

These angles are directly next to each other and share a common side.

Hope this helps!! :)

4 0
2 years ago
Harley is on a trip with her dad. Her dad tells her that they've traveled 182.6 miles and they are 83% of the way to their desti
Natali5045456 [20]
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8 0
3 years ago
1 A can in the shape of a cylinder has a diameter of 6 centimeters and a height of 10
Ronch [10]

Answer:

radius r = 3 cm

height h = 10 cm

volume V = 282.743339 cm^3

lateral surface area L = 188.495559 cm^2

top surface area T = 28.2743339 cm^2

base surface area B = 28.2743339 cm^2

total surface area A = 245.044227 cm^2

In Terms of Pi π

volume V = 90 π cm3

lateral surface area L = 60 π cm^2

top surface area T = 9 π cm^2

base surface area B = 9 π cm^2

total surface area A = 78 π cm^2

Step-by-step explanation:

Cylinder Formulas in terms of r and h:

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V = πr2h

Calculate the lateral surface area of a cylinder (just the curved outside)**:

L = 2πrh

Calculate the top and bottom surface area of a cylinder (2 circles):

T = B = πr2

Total surface area of a closed cylinder is:

A = L + T + B = 2πrh + 2(πr2) = 2πr(h+r)

Agenda: r = radius

h = height

V = volume

L = lateral surface area

T = top surface area

B = base surface area

A = total surface area

π = pi = 3.1415926535898

√ = square root

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Answer:

6.4

Step-by-step explanation:

Well the radius of the whole pizza is 8

So the total area is 64π

And 64 / 10 = 6.4

7 0
3 years ago
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