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2 years ago

Reasoning Explain why either a or b must be 0 if ab = 0, but neither a nor b

1 answer:

7 0

By the zero product property, a or b must be 0 if ab = 0. Or you could solve for each variable.

Divide both sides by b:
b=0/a —> b=0

Divide both sides by b:
a=0/b —> a=0

Hmm A could be 4 and b could be 1 because 4*1=4

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NO LINKS OR ANSWERING QUESTIONS YOU DON'T KNOW!!! THIS IS NOT A TEST OR AN ASSESSMENT!! Please help me with these math questions

Art [367]

Answer:

See below

Step-by-step explanation:

3. What are two ways that a vector can be represented?

Considering a vector $\vec{v}$ in some vector space $\mathbb R^n$ we have

$\vec{v} = \langle a,b\rangle$

This is the component form. I don't like that way. It is probably used in high school, but

$\vec{v} = \begin{pmatrix} a\\ b\\ \end{pmatrix}$

is preferable because the inner product on $\mathbb R^n$ is defined to be

$\langle a,b\rangle := \sum_{i = 1}^n a_i b_i$

You can also write it using linear form such as $\vec{v} = 2i+2j$

For this question, I think you meant

vectors

$\vec{u_1} = (-8, 12)$

$\vec{u_2} = (13, 15)$

Once

$\cos(\theta)=\dfrac{\vec{u_1} \cdot\vec{u_2}}{||\vec{u_1}||||\vec{u_2}||}$

Considering that the dot product is

$\vec{u_1}\cdot \vec{u_2} = (-8)\cdot 13 + 12\cdot 15 = -104+180= 76$

and the norm of $\vec{u_1}$ is $||\vec{u_1}|| = \sqrt{(-8)^2 + 12^2} = \sqrt{64 + 144}= \sqrt{208}$

and the norm of $\vec{u_2}$ is $||\vec{u_2}|| = \sqrt{13^2 + 15^2} = \sqrt{169 + 225}= \sqrt{394}$

Thus,

$\cos(\theta)=\dfrac{76}{\sqrt{208} \sqrt{394}} = \dfrac{19}{\sqrt{13}\sqrt{394}}=\dfrac{19}{\sqrt{5122}}$

$\therefore \theta = \arccos \left(\dfrac{19}{\sqrt{5122}} \right)$

3 0

2 years ago

7/4x^2 -2 = - 0.05x + 4

nata0808 [166]

Answer:

$x1=\frac{-2-2\sqrt{29401} }{245} x2=\frac{-2+2\sqrt{29401} }{245}$

Step-by-step explanation:

Step One: Convert

49/16x^2-2=-0.05x+4

Step Two: Multiply Both Sides by 80

245x^2-160=-4x+320

Step Three: Move everything to the left

245x^2+4x-480=0

Final Step: Quadratic Formula

$x1=\frac{-2-2\sqrt{29401} }{245} x2=\frac{-2+2\sqrt{29401} }{245}$

6 0

3 years ago

What does it mean to “solve for a variable”?

madam [21]

Answer:

it means to find the undefined number

we should solve for the variable to find the answer to the equation

we solve for the variable by using the elimination method

Step-by-step explanation:

4 0

3 years ago

HELP PLEASE !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

aleksandrvk [35]

50km to 80km is 30km

10c to -80c is -90c

and since it linear (Which means the change is constant or the same)

every 10 km show a -30c decrease

60 km is -20c

70km is -50c

answer is c

5 0

2 years ago

How can a rational number and irrational number when multiplied together make a irrational number ?

pochemuha

Answer:

"The product of a rational number and an irrational number is SOMETIMES irrational." If you multiply any irrational number by the rational number zero, the result will be zero, which is rational. Any other situation, however, of a rational times an irrational will be irrational

A better statement would be:

"The product of a non-zero rational number and an irrational number is irrational

6 0

2 years ago