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liberstina [14]

4 years ago

10

Charlie made identical necklaces, each having beads and a pendant. The total cost of the beads and pendants for all necklaces wa

s . If the beads cost for each necklace, how much did each pendant cost?

1 answer:

irinina [24]4 years ago

6 0

Answer:

Step-by-step explanation:

You didnt give a price

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Find the absolute maximum and absolute minimum values of the function f(x, y) = x 2 + y 2 − x 2 y + 7 on the set d = {(x, y) : |

dsp73

Looks like $f(x,y)=x^2+y^2-x^2y+7$ .

$f_x=2x-2xy=0\implies2x(1-y)=0\implies x=0\text{ or }y=1$

$f_y=2y-x^2=0\implies2y=x^2$

If $x=0$ , then $y=0$ - critical point at (0, 0).
If $y=1$ , then $x=\pm\sqrt2$ - two critical points at $(-\sqrt2,1)$ and $(\sqrt2,1)$

The latter two critical points occur outside of $D$ since $|\pm\sqrt2|>1$ so we ignore those points.

The Hessian matrix for this function is

$H(x,y)=\begin{bmatrix}f_{xx}&f_{xy}\\f_{yx}&f_{yy}\end{bmatrix}=\begin{bmatrix}2-2y&-2x\\-2x&2\end{bmatrix}$

The value of its determinant at (0, 0) is $\det H(0,0)=4>0$ , which means a minimum occurs at the point, and we have $f(0,0)=7$ .

Now consider each boundary:

If $x=1$ , then

$f(1,y)=8-y+y^2=\left(y-\dfrac12\right)^2+\dfrac{31}4$

which has 3 extreme values over the interval $-1\le y\le1$ of 31/4 = 7.75 at the point (1, 1/2); 8 at (1, 1); and 10 at (1, -1).

If $x=-1$ , then

$f(-1,y)=8-y+y^2$

and we get the same extrema as in the previous case: 8 at (-1, 1), and 10 at (-1, -1).

If $y=1$ , then

$f(x,1)=8$

which doesn't tell us about anything we don't already know (namely that 8 is an extreme value).

If $y=-1$ , then

$f(x,-1)=2x^2+8$

which has 3 extreme values, but the previous cases already include them.

Hence $f(x,y)$ has absolute maxima of 10 at the points (1, -1) and (-1, -1) and an absolute minimum of 0 at (0, 0).

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3 years ago

If ln(4x+y)=2x-3,then dy/dx=

Viktor [21]

$\ln(4x+y)=2x-3$

Differentiate both sides wrt $x$ :

$\dfrac{\mathrm d(\ln(4x+y))}{\mathrm dx}=\dfrac{\mathrm d(2x-3)}{\mathrm dx}$

By the chain rule, we get

$\dfrac1{4x+y}\dfrac{\mathrm d(4x+y)}{\mathrm dx}=2$

$\dfrac{4+\frac{\mathrm dy}{\mathrm dx}}{4x+y}=2$

Solve for $\frac{\mathrm dy}{\mathrm dx}$ :

$4+\dfrac{\mathrm dy}{\mathrm dx}=8x+2y$

$\boxed{\dfrac{\mathrm dy}{\mathrm dx}=8x+2y-4}$

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3 years ago

What do you call to the set of ordered pairs

satela [25.4K]

Answer:

A relation is a set of ordered pairs. The set of all first components of the ordered pairs is called the domain of the relation and the set of all second components of the ordered pairs is called the range of the relation.

Step-by-step explanation:

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4 years ago

Read 2 more answers

I need help with #47 to #50 ASAP…. Please help me with it

Ksenya-84 [330]

Step-by-step explanation:

a triangular number n is the sum of all natural numbers <= n.

t1 = 1

t2 = 1+2 = 3

t3 = 1+2+3 = 6

t4 = 1+2+3+4 = 10

...

so,

tn = tn-1 + n

47.

1×8 + 1 = 9 is a square number.

3×8 + 1 = 25 is a square number

6×8 + 1 = 49 is a square number

10×8 + 1 = 81 is a square number

48.

1/3 = 0 remainder 1

3/3 = 1 remainder 0

6/3 = 2 remainder 0

10/3 = 3 remainder 1

15/3 = 5 remainder 0

21/3 = 7 remainder 0

28/3 = 9 remainder 1

so, there seems to be a pattern 1 0 0 1 0 0 1 0 0 1 ...

49.

1/4 = 0 remainder 1

4/4 = 1 remainder 0

9/4 = 2 remainder 1

16/4 = 4 remainder 0

25/4 = 6 remainder 1

36/4 = 9 remainder 0

49/4 = 12 remainder 1

so, there seems to be a pattern 1 0 1 0 1 0 1 0 1 0 1 ...

50.

polygonal numbers is the real name for this.

the formula for dimensions = 5 is

(3n² − n)/2

for dimensions = 6 it is

2n² - n

so, dimensions=5 (and therefore dividing also by 5) we get the remainders

1/5 = 0 remainder 1

5/5 = 1 remainder 0

12/5 = 2 remainder 2

22/5 = 4 remainder 2

35/5 = 7 remainder 0

51/5 = 10 remainder 1

70/5 = 14 remainder 0

92/5 = 18 remainder 2

117/5 = 23 remainder 2

145/5 = 29 remainder 0

here the pattern is 1 0 2 2 0 1 0 2 2 0 1 0 2 2 0 ...

dimensions=6 (and therefore dividing also by 6) we get the remainders

1/6 = 0 remainder 1

6/6 = 1 remainder 0

15/6 = 2 remainder 3

28/6 = 4 remainder 4

45/6 = 7 remainder 3

66/6 = 11 remainder 0

91/6 = 15 remainder 1

120/6 = 20 remainder 0

153/6 = 25 remainder 3

190/6 = 31 remainder 4

231/6 = 38 remainder 3

276/6 = 46 remainder 0

325/6 = 54 remainder 1

here the pattern is 1 0 3 4 3 0 1 0 3 4 3 0 1 0 3 4 3 0 ...

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3 years ago

the reporter asked 12 people in the company why they liked working for their boss and found 8 people of the said it was beacuse

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