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Jobisdone [24]
3 years ago
9

Find the max and min values of f(x,y,z)=x+y-z on the sphere x^2+y^2+z^2=81

Mathematics
1 answer:
Anton [14]3 years ago
5 0
Using Lagrange multipliers, we have the Lagrangian

L(x,y,z,\lambda)=x+y-z+\lambda(x^2+y^2+z^2-81)

with partial derivatives (set equal to 0)

L_x=1+2\lambda x=0\implies x=-\dfrac1{2\lambda}
L_y=1+2\lambda y=0\implies y=-\dfrac1{2\lambda}
L_z=-1+2\lambda z=0\implies z=\dfrac1{2\lambda}
L_\lambda=x^2+y^2+z^2-81=0\implies x^2+y^2+z^2=81

Substituting the first three equations into the fourth allows us to solve for \lambda:

x^2+y^2+z^2=\dfrac1{4\lambda^2}+\dfrac1{4\lambda^2}+\dfrac1{4\lambda^2}=81\implies\lambda=\pm\dfrac1{6\sqrt3}

For each possible value of \lambda, we get two corresponding critical points at (\mp3\sqrt3,\mp3\sqrt3,\pm3\sqrt3).

At these points, respectively, we get a maximum value of f(3\sqrt3,3\sqrt3,-3\sqrt3)=9\sqrt3 and a minimum value of f(-3\sqrt3,-3\sqrt3,3\sqrt3)=-9\sqrt3.
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The current population of a town is 10,000 and its growth in years can be represented by P(t) = 10,000(0.2)^t, where t is the ti
DiKsa [7]

Answer:

1) 20%

2) Choice a.

Step-by-step explanation:

P(t)=10000(0.2)^t

1) P(0) is the population initially.

P(1) is the population after a year.

\frac{P(1)}{P(0)} represents the population increase factor.

So let's evaluate that fraction:

\frac{P(1)}{P(0)}

\frac{10000(0.2)^1}{10000(0.2)^0}

\frac{0.2^1}{0.2^0}=\frac{0.2}{1}=0.2

0.2=20%

2) Let's figure out the population growth in terms of months instead of years.

P(t)=10000(0.2)^{t}

We want t to represent months.

A full year is 12 months, in a full year we have that P(1)=10000(0.2)^1=10000(0.2)=2000

So we want a new P such that P(12)=2000 since 12 months equals a year.

Let's look at the functions given to see which gives us this:

a) P(12)=10000(0.87449)^{12}=2000 \text{approximately}

b) P(12)=10000(0.87449)^{12(12)}=0 \text{ approximately}

c) P(12)=10000(0.87449)^{\frac{1}{12}}=9889 \text{approximately}

d) P(12)=10000(0.87449)^{12+12}=400 \text{approximately}

So a is the function we want.

Also another way to look at this:

P(t)=10000(.2)^t where t is in years.

P(t)=10000(.2^\frac{1}{12})^t where t is in months.

And .2^\frac{1}{12}=0.874485 \text{approximately}

8 0
4 years ago
What is the square root of 75 in the simplest form
lesantik [10]

Answer:

5\sqrt{3}

Step-by-step explanation:

\sqrt{75} = \sqrt{5^{2}*3} =5\sqrt{3}

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Through a regular hexagon whose base edge is 8cm and whose height ii 12cma hole in the shape of the right prism with ots end bei
guapka [62]

The total surface area of the remaining solid is 48(4+✓3) centimeters square.

<h3>How to calculate the surface area?</h3>

Through a regular hexagonal prism whose base edge is 8 cm and the height is 12 cm, a hole in the shape of a right prism.

The formula for the total surface area will be:

= Total surface area=2(area of the base)+ parameter of base × height

where,

Height= 8cm

Parameter of base=12(2) = 24

Area of the base= 6×✓3/4×4² = 64✓3/4

The surface area of the remaining solid will be:

= 2(64✓3/4) + 24 × 8

= 2(64✓3/4 + 192

With the hole is a rhombus prism with the following parameters:

diagonal 1 = 6, diagonal 2 = 8, height = 12

The volume is:

V1 =0.5 × d1 × d2 × h

V1 = 0.5 × 6 × 8 × 12

V1 = 96

The dimensions of the hexagonal prism are:

Base edge (a) = 8

Height (h) = 12

The volume is

V2 = (3✓(3)/2)a²h

V2 = (3✓3)/2) × 8² × 12

V2 = 1152✓3

The remaining volume is

V = V2 -V1

V = 1152✓3 - 96

Learn more about the hexagonal prism on:

brainly.com/question/27127032

#SPJ4

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2 years ago
James buys x books at a used-book sale. Enter an inequality that can be used to find the number of books James buys (x) when the
den301095 [7]

2x<15

Step-by-step explanation:

2×15=30 if he spends less than he would have to be below 15 please give brainliest

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