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2 years ago

Use logarithms to solve the equation for t. 1/5 e^(-2 t) = 0.9

Mathematics

1 answer:

blondinia [14]2 years ago

3 0

Answer:

$t = - \frac{ln(4.5)}{2}$

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The radius of a sphere decreases at a rate of 6 m/sec. find the rate at which the surface area decreases when the radius is 20 m

DanielleElmas [232]

The radius of the sphere decreases at the rate of 6 m/ sec

That is, $\frac{dr}{dt}=-6$

Surface Area of the sphere of radius r is given by $S=4\pi r^2$

Differentiating with respect to t,

$\frac{dS}{dt}=4\pi (2r)\frac{dr}{dt}=8\pi r\frac{dr}{dt}$

$\frac{dS}{dt}=8\pi (20)^2(-6)=-960\pi \: m^2/sec$

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3 years ago

nick has to build a brick wall. Each row of the wall requires 6/2 bricks. There are 10 rows in the wall. How many bricks will ni

alex41 [277]

Answer:

D. 10 x 6/2

Step-by-step explanation:

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2 years ago

A statistician uses Chebyshev's Theorem to estimate that at least 15 % of a population lies between the values 9 and 20. Use thi

rjkz [21]

Answer:

\mu = 14.5\\

\sigma = 5.071\\

k = 1.084

Step-by-step explanation:

given that a statistician uses Chebyshev's Theorem to estimate that at least 15 % of a population lies between the values 9 and 20.

i.e. his findings with respect to probability are

$P(9$

Recall Chebyshev's inequality that

$P(|X-\mu |\geq k\sigma )\leq {\frac {1}{k^{2}}}\\P(|X-\mu |\leq k\sigma )\geq 1-{\frac {1}{k^{2}}}\\$

Comparing with the Ii equation which is appropriate here we find that

$\mu =14.5$

Next what we find is

$k\sigma = 5.5\\1-\frac{1}{k^2} =0.15\\\frac{1}{k^2}=0.85\\k=1.084\\1.084 (\sigma) = 5.5\\\sigma = 5.071$

Thus from the given information we find that

$\mu = 14.5\\\sigma = 5.071\\k = 1.084$

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3 years ago

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2 years ago

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Hoochie [10]

Answer:

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Step-by-step explanation:

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1 year ago