If the equation yx = zx is true, when yx is positive, x /= 0, and z is

Mathematics

1 answer:

denis23 [38]2 years ago

5 0

Answer: negative

Step-by-step explanation:

With yx = zx, then by the Multiplicative Property of Equality, y = z. Since z is a negative integer, then y is also a negative integer. Since yx is positive, with y equal to a negative integer, then x is negative.

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Let φ(x, y) = arctan (y/x) .

Alexandra [31]

Answer:

a) $\large F(x,y)=(-\frac{y}{x^2+y^2},\frac{x}{x^2+y^2})$

b) $\large \mathbb{R}^2-\{(0,0)\}$

c) the points of the form (x, -x) for x≠0

Step-by-step explanation:

If φ(x, y) = arctan (y/x), the vector field F = ∇φ would be

$\large F(x,y)=(\frac{\partial \phi}{\partial x},\frac{\partial \phi}{\partial y})$

On one hand we have,

$\large \frac{\partial \phi}{\partial x}=\frac{\partial arctan(y/x)}{\partial x}=\frac{-y/x^2}{1+(y/x)^2}=-\frac{y/x^2}{1+y^2/x^2}=\\\\=-\frac{y/x^2}{(x^2+y^2)/x^2}=-\frac{y}{x^2+y^2}$

On the other hand,

$\large \frac{\partial \phi}{\partial y}=\frac{\partial arctan(y/x)}{\partial y}=\frac{1/x}{1+(y/x)^2}=\frac{1/x}{1+y^2/x^2}=\\\\=\frac{1/x}{(x^2+y^2)/x^2}=\frac{x}{x^2+y^2}$

$\large F(x,y)=(-\frac{y}{x^2+y^2},\frac{x}{x^2+y^2})$

The domain of definition of F is

$\large \mathbb{R}^2-\{(0,0)\}$

i.e., all the plane X-Y except the (0,0)

Here we want to find all the points such that

$\large (-\frac{y}{x^2+y^2},\frac{x}{x^2+y^2})=(k,k)$

where k is a real number other than 0.

But this means

$\large -\frac{y}{x^2+y^2}=\frac{x}{x^2+y^2}\Rightarrow y=-x$

So, all the points in the line y = -x except (0,0) are parallel to the vector field F, that is, the points (x, -x) with x≠ 0

8 0

2 years ago

Larry earns $11.25/hour selling televisions. He also earns 4.5% commission on his sales. What is his

monitta

Answer:

C) $573.75

Step-by-step explanation:

We can come up with the equation of this Gross Weekly pay as:

$P(t)=11.25t+0.045S$

Where P is the amount Larry will get paid, t is the time worked and S is the amount of sales he generated that week. This was derived from the fact that 11.25 is the slope and 0.045S is the y-intercept. By plugging in those values we have:

$P(35)=11.25(35)+0.045(4000)=573.75$