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3 years ago

14

The speed of a train is 60 miles per hour. In 2 hours, the train will cover miles, In 4 hours, the train will cover miles. The t

rain covered more miles in 4 hours than it did in 2 hours.

1 answer:

Hitman42 [59]3 years ago

7 0

The train is going 60 miles per hour

In 2 hours

60 * 2 = ?

In 4 hours

60 * 4 = ?

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15. If x=a Sin2t (I+Cos2t) and y=b Cos 2t (1-Cos2t) then find<br>dy/dx at =22/7*4<br>

Sav [38]

By the chain rule,

$\dfrac{\mathrm dy}{\mathrm dx}=\dfrac{\mathrm dy}{\mathrm dt}\dfrac{\mathrm dt}{\mathrm dx}\implies\dfrac{\mathrm dy}{\mathrm dx}=\dfrac{\frac{\mathrm dy}{\mathrm dt}}{\frac{\mathrm dx}{\mathrm dt}}$

It looks like we're given

$\begin{cases}x=a\sin(2t)(1+\cos(2t))\\y=b\cos(2t)(1-\cos(2t))\end{cases}$

where <em>a</em> and <em>b</em> are presumably constant.

Recall that

$\cos^2t=\dfrac{1+\cos(2t)}2$

$\sin^2t=\dfrac{1-\cos(2t)}2$

so that

$\begin{cases}x=2a\sin(2t)\cos^2t\\y=2b\cos(2t)\sin^2t\end{cases}$

Then we have

$\dfrac{\mathrm dx}{\mathrm dt}=4a\cos(2t)\cos^2t-4a\sin(2t)\cos t\sin t$

$\dfrac{\mathrm dy}{\mathrm dt}=-4b\sin(2t)\sin^2t+4b\cos(2t)\sin t\cos t$

$\implies\dfrac{\mathrm dy}{\mathrm dx}=\dfrac{4b\cos(2t)\sin t\cos t-4b\sin(2t)\sin^2}{4a\cos(2t)\cos^2t-4a\sin(2t)\cos t\sin t}$

$\implies\boxed{\dfrac{\mathrm dy}{\mathrm dx}=\dfrac ba\tan t}$

where the last reduction follows from dividing through everything by $\cos(2t)\cos^2t$ and simplifying.

I'm not sure at which point you're supposed to evaluate the derivative (22/7*4, as in 88/7? or something else?), so I'll leave that to you.

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3 years ago

A firm has the following fixed proportion production function q = min(k, 2l). a. Find the firms long-run total, average, and mar

Yuri [45]

Answer:

I think its right

Step-by-step explanation:

a) In the long run, we have, 5k=10 and k=2l Thus, C=2l+3l= 5l=0.5q Thus, AC=5l/10l =0.5 MC=0.5 b) In the short run, k=10 Q=min(50,10l) If l<5, q=10l. C=10+3l= 10+0.3q Thus, AC=10/q + 0.3 If l>5, q=50. C= 10+3l AC= (10+3l)/50 If q>50, then MC...

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2 years ago

Solve 5x+7 > 17.<br> {x1x<2}<br> O {XIX> 2}<br> O {xIx>-2}<br> O {x1x < -2}

fgiga [73]

Answer:

The answer is $x > 2$

Step-by-step explanation:

to solve this inequality:

$5x+7 > 17$

Put "-7" on both sides

$5x+10$

divide by 5 on both sides

your answer should be 2.

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2 years ago

3 spheres of diameter 6cm,8cm and 10cm are melted to form a single sphere .find the diameter of the sphere.

julia-pushkina [17]

Answer:

Step-by-step explanation:

6/2=3 cm is the radius V(4/3πr³) = 4/3.π.27…(1)

8/2= 4 cm is the radius and V = 4/3.π.64…..(2)

10/2=5 cm is the radius and V = 4/3.π.125…(3)

The Total Volume is the addition of (1)+(2)+(3) or 4/3π (27+64+125) or New volume is 4/3.π.(216) cm³ and therefore...

The radius of the New Solid Sphere is Cube Root of 216 (r³) = √6.6.6 or r = 6 cm and the diameter is 6.2 = 12 cms.

12 cms answer. Brainlist please?

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3 years ago

A triangle drawn on a Cartesian plane has vertices p(-10,-2) Q(-10,6) and R(5,2). Calculate the perimeter,in units of the triang

lakkis [162]

Answer:

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Step-by-step explanation:

The Frog and the Ox are a great place to work for and it

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3 years ago