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3 years ago

Whats v= π r^2h ; (h)

Mathematics

1 answer:

evablogger [386]3 years ago

4 0

It's the formula for the volume of a cylinder with radius r and height h.

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Find the values of x and y

zhuklara [117]

You can use a tangent:

$tangent=\dfrac{opposite}{adjacent}$

We have opposite = 17 and adjacent = x.

$\tan30^o=\dfrac{\sqrt3}{3}$

substitute:

$\dfrac{17}{x}=\dfrac{\sqrt3}{3}$ cross multiply

$x\sqrt3=(3)(17)$ multiply both sides by √3

$x(\sqrt3)(\sqrt3)=51\sqrt3$

$3x=51\sqrt3$ divide both sides by 3

$x=17\sqrt3$

Use the Pythagorean theorem:

$y^2=(17\sqrt3)^2+17^2\\\\y^2=289(\sqrt3)^2+289\\\\y^2=289\cdot3+289\\\\y^2=867+289\\\\y^2=1156\to y=\sqrt{1156}\\\\y=34$

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Other method.

$30^o-60^o-90^o$ triangle.

The sides are in the ratio $1:2:\sqrt3\to17:y:x$

Therefore

$17:(2\cdot17):(17\sqrt3)\to17:34:17\sqrt3\to x=34,\ y=17\sqrt3$

4 0

3 years ago

Help me solve this..! Please!

stiv31 [10]

Answer:

x=2

Solve for x by simplifying both sides of the equation, then isolating the variable.

3 0

3 years ago

Find the absolute extrema for f(x,y)=4-x^2-y^4+1/2y^2 over the closed disk D:x^2+y^2 is less than or equal to 1

algol [13]

Find the critical points of $f(x,y)$ :

$\dfrac{\partial f}{\partial x}=-2x=0\implies x=0$

$\dfrac{\partial f}{\partial y}=y-4y^3=y(1-4y^2)=0\implies y=0\text{ or }y=\pm\dfrac12$

All three points lie within $D$ , and $f$ takes on values of

$\begin{cases}f(0,0)=4\\f\left(0,-\frac12\right)=\frac{65}{16}\\f\left(0,\frac12\right)=\frac{65}{16}\end{cases}$

Now check for extrema on the boundary of $D$ . Convert to polar coordinates:

$f(x,y)=f(\cos t,\sin t)=g(t)=4-\cos^2-\sin^4t+\dfrac12\sin^2t=3+\dfrac32\sin^2t-\sin^4t$

Find the critical points of $g(t)$ :

$\dfrac{\mathrm dg}{\mathrm dt}=3\sin t\cos t-4\sin^3t\cos t=\sin t\cos t(3-4\sin^2t)=0$

$\implies\sin t=0\text{ or }\cos t=0\text{ or }\sin t=\pm\dfrac{\sqrt3}2$

$\implies t=n\pi\text{ or }t=\dfrac{(2n+1)\pi}2\text{ or }\pm\dfrac\pi3+2n\pi$

where $n$ is any integer. There are some redundant critical points, so we'll just consider $0\le t< 2\pi$ , which gives

$t=0\text{ or }t=\dfrac\pi3\text{ or }t=\dfrac\pi2\text{ or }t=\pi\text{ or }t=\dfrac{3\pi}2\text{ or }t=\dfrac{5\pi}3$

which gives values of

$\begin{cases}g(0)=3\\g\left(\frac\pi3\right)=\frac{57}{16}\\g\left(\frac\pi2\right)=\frac72\\g(\pi)=3\\g\left(\frac{3\pi}2\right)=\frac72\\g\left(\frac{5\pi}3\right)=\frac{57}{16}\end{cases}$

So altogether, $f(x,y)$ has an absolute maximum of 65/16 at the points (0, -1/2) and (0, 1/2), and an absolute minimum of 3 at (-1, 0).

5 0

2 years ago

A lathe is set to cut bars of steel into lengths of 6 centimeters. the lathe is considered to be in perfect adjustment if the av

Nitella [24]

The hypothesis testing for this problem is:
a. The hypothesis for this problem are:
Null: H0: μ=6
Alternative: Ha: μ≠6

b. Test
T-statistics = (6.08 - 6) / 0.44* √(121) = 2

c. P value = 0.047759

Since our p-value is smaller than the significant level of 0.05, we can say that we reject the null hypothesis.

Conclusion: there is enough evidence to say lathe is not in perfect adjustment.

4 0

3 years ago

Which system of equations has the same solution as the system below

QveST [7]

Answer:

None of the above.

Step-by-step explanation:

The system of equations which should have the same solution as the system below;

x + 4y = 11

4x + 2y = 16

x + 4y = 11

-8x - 4y = - 32

This system of equations is missing from your choices.

The trick is that -2 is multiplied to the second equation of the first system.

i.e -2 (4x + 2y = 16) gives; -8x - 4y = -32

3 0

3 years ago