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3 years ago

You are taking a test in science. For every 3 questions, you have 5 minutes.

Mathematics

1 answer:

Eduardwww [97]3 years ago

7 0

Answer:

50 minutes

Step-by-step explanation:

5•10

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26. Define a relation ∼ ∼ on R 2 R2 by stating that ( a , b ) ∼ ( c , d ) (a,b)∼(c,d) if and only if a 2 + b 2 ≤ c 2 + d 2 . a2+

Tresset [83]

Answer:

~ is reflexive.

~ is asymmetric.

~ is transitive.

Step-by-step explanation:

~ is reflexive:

i.e., to prove $\forall (a, b) \in \mathbb{R}^2$ , $(a, b) R(a, b)$ .

That is, every element in the domain is related to itself.

The given relation is $\sim: (a,b) \sim (c, d) \iff a^2 + b^2 \leq c^2 + d^2$

Reflexive:

$(a, b) \sim (a, b)$ since $a^2 + b^2 = a^2 + b^2$

This is true for any pair of numbers in $\mathbb{R}^2$ . So, $\sim$ is reflexive.

Symmetry:

$\sim$ is symmetry iff whenever $(a, b) \sim (c, d)$ then $(c, d) \sim (a, b)$ .

Consider the following counter - example.

Let (a, b) = (2, 3) and (c, d) = (6, 3)

$a^2 + b^2 = 2^2 + 3^2 = 4 + 9 = 13$

$c^2 + d^2 = 6^2 + 3^2 = 36 + 9 = 42$

Hence, $(a, b) \sim (c, d)$ since $a^2 + b^2 \leq c^2 + d^2$

Note that $c^2 + d^2 \nleq a^2 + b^2$

Hence, the given relation is not symmetric.

Transitive:

$\sim$ is transitive iff whenever $(a, b) \sim (c, d) \hspace{2mm} \& \hspace{2mm} (c, d) \sim (e, f)$ then $(a, b) \sim (e, f)$

To prove transitivity let us assume $(a, b) \sim (c, d)$ and $(c, d) \sim (e, f)$ .

We have to show $(a, b) \sim (e, f)$

Since $(a, b) \sim (c, d)$ we have: $a^2 + b^2 \leq c^2 + d^2$

Since $(c, d) \sim (e, f)$ we have: $c^2 + d^2 \leq e^2 + f^2$

Combining both the inequalities we get:

$a^2 + b^2 \leq c^2 + d^2 \leq e^2 + f^2$

Therefore, we get: $a^2 + b^2 \leq e^2 + f^2$

Therefore, $\sim$ is transitive.

Hence, proved.

3 0

3 years ago

Re-write the quadratic function below in Standard Form<br> y = 9(x - 1)(x + 3)

Maksim231197 [3]

Y=9(x^2+3x-x-3)
y=9(x^2+2x-3)
y=9x^2+18x-27

4 0

3 years ago

Peter ran 4 ⅔ miles on Tuesday. On Wednesday, he ran ⅘ of this distance. How far did he run?

larisa86 [58]

Answer:

3.73333

Step-by-step explanation:

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3 years ago

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A bicycle wheel with radius 26" rotates through an arc that measures 80°. What is the length of the arc of the tire that touched

Bad White [126]

$\bf \textit{arc's length}\\\\
s=\cfrac{\theta \pi r}{180}\quad 
\begin{cases}
r=radius\\
\theta =angle~in\\
\qquad degrees\\
------\\
\theta = 80\\
r=26
\end{cases}\implies s=\cfrac{80\cdot \pi \cdot 26}{180}$

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3 years ago

-5(x+2)+3x= Which expression can be written in the box on the other side of the equation

storchak [24]

Answer:

O-2(x+5)

Step-by-step explanation:

I have to much time on my hands

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3 years ago

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