Tìm mệnh đề đúng trong các mệnh đề sau:

Two thirds the sum of 30 and a number is 26 write this statement out as an equation and solve

zloy xaker [14]

Answer:s

Step-by-step explanation:

Let the number be x

2/3(30+x) = 26

2(30+x) = 26(3)

60 + 2x = 78

2x = 78 - 60

2x = 18

x = 18/2

x = 9

7 0

2 years ago

NO LINKS OR FILES!

Archy [21]

(a) If the particle's position (measured with some unit) at time t is given by s(t), where

$s(t) = \dfrac{5t}{t^2+11}\,\mathrm{units}$

then the velocity at time t, v(t), is given by the derivative of s(t),

$v(t) = \dfrac{\mathrm ds}{\mathrm dt} = \dfrac{5(t^2+11)-5t(2t)}{(t^2+11)^2} = \boxed{\dfrac{-5t^2+55}{(t^2+11)^2}\,\dfrac{\rm units}{\rm s}}$

(b) The velocity after 3 seconds is

$v(3) = \dfrac{-5\cdot3^2+55}{(3^2+11)^2} = \dfrac{1}{40}\dfrac{\rm units}{\rm s} = \boxed{0.025\dfrac{\rm units}{\rm s}}$

(c) The particle is at rest when its velocity is zero:

$\dfrac{-5t^2+55}{(t^2+11)^2} = 0 \implies -5t^2+55 = 0 \implies t^2 = 11 \implies t=\pm\sqrt{11}\,\mathrm s \imples t \approx \boxed{3.317\,\mathrm s}$

(d) The particle is moving in the positive direction when its position is increasing, or equivalently when its velocity is positive:

$\dfrac{-5t^2+55}{(t^2+11)^2} > 0 \implies -5t^2+55>0 \implies -5t^2>-55 \implies t^2 < 11 \implies |t|$

In interval notation, this happens for t in the interval (0, √11) or approximately (0, 3.317) s.

(e) The total distance traveled is given by the definite integral,

$\displaystyle \int_0^8 |v(t)|\,\mathrm dt$

By definition of absolute value, we have

$|v(t)| = \begin{cases}v(t) & \text{if }v(t)\ge0 \\ -v(t) & \text{if }v(t)$

In part (d), we've shown that v(t) > 0 when -√11 < t < √11, so we split up the integral at t = √11 as

$\displaystyle \int_0^8 |v(t)|\,\mathrm dt = \int_0^{\sqrt{11}}v(t)\,\mathrm dt - \int_{\sqrt{11}}^8 v(t)\,\mathrm dt$

and by the fundamental theorem of calculus, since we know v(t) is the derivative of s(t), this reduces to

$s(\sqrt{11})-s(0) - s(8) + s(\sqrt{11)) = 2s(\sqrt{11})-s(0)-s(8) = \dfrac5{\sqrt{11}}-0 - \dfrac8{15} \approx 0.974\,\mathrm{units}$

7 0

2 years ago

Which of the following is a way that citizens can directly influence law-making and public policy?

sweet [91]

Answer: A way citizens can directly influence the public policy is by following it or not. If there is a policy that no one agrees with, they will not follow it and show that the policy is wrong. When this is done, the policy will go away. That is how citizens can directly change this.

Step-by-step explanation:

6 0

2 years ago

Blue Bird began at the location (6,0) and hit the ground at (26,0). Write a polynomial equation that could represent his flight

Bogdan [553]

Skjsbdksnsnsmsmznsjdhsbdjdns

6 0

3 years ago

A baker makes 84 loaves of bread, she burns 4. What fraction of the loaves does the burn? Simplify your answer.

svetoff [14.1K]

Answer:

1/21

Step-by-step explanation:

The baker makes 84 loaves of bread,

Out of the 84 bread, 4 of them got burn.

Fraction that the loaves does the burn will be expressed in 4/84 = 1/21.

3 0

2 years ago