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2 years ago

10

Martha puts $240 in a savings account that earns 2% interest. if she leaves her money in the account for 5 years, how much simpl

e interest will she earn
Letter L by the way

1 answer:

Cerrena [4.2K]2 years ago

6 0

Answer:

The final balance is $265.24.

The total compound interest is $25.24.

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The graphs of the polar curves r = 4 and r = 3 + 2cosθ are shown in the figure above. The curves intersect at θ = π/3 and θ = 5π

Gennadij [26K]

(a)

$\displaystyle \frac{1}{2} \cdot \int_{\frac{\pi}{3}}^{\frac{5\pi}{3}} \left(4^2 - (3 + 2\cos\theta)^2 \right) \, d\theta$

or, via symmetry

$\displaystyle\frac{1}{2} \cdot 2 \int_{\frac{\pi}{3}}^{\pi} \left(4^2 - (3 + 2\cos\theta)^2 \right) \, d\theta$

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(b)

By the chain rule:

$\displaystyle \frac{dy}{dx} = \frac{ dy/ d\theta}{ dx/ d\theta}$

For polar coordinates, x = rcosθ and y = rsinθ. Since
<span>r = 3 + 2cosθ, it follows that

$x = (3 + 2\cos\theta) \cos \theta \\ 
y = (3 + 2\cos\theta) \sin \theta$

Differentiating with respect to theta

$\begin{aligned}
\displaystyle \frac{dy}{dx} &= \frac{ dy/ d\theta}{ dx/ d\theta} \\
&= \frac{(3 + 2\cos\theta)(\cos\theta) + (-2\sin\theta)(\sin\theta)}{(3 + 2\cos\theta)(-\sin\theta) + (-2\sin\theta)(\cos\theta)} \\ \\
\left.\frac{dy}{dx}\right_{\theta = \frac{\pi}{2}}
&= 2/3
\end{aligned}$

2/3 is the slope

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(c)

"</span><span>distance between the particle and the origin increases at a constant rate of 3 units per second" implies dr/dt = 3

A</span>ngle θ and r are related via <span>r = 3 + 2cosθ, so implicitly differentiating with respect to time

</span><span /> $\displaystyle\frac{dr}{dt} = -2\sin\theta \frac{d\theta}{dt} \quad \stackrel{\theta = \pi/3}{\implies} \quad 3 = -2\left( \frac{\sqrt{3}}{2}}\right) \frac{d\theta}{dt} \implies \\ \\ \frac{d\theta}{dt} = -\sqrt{3} \text{ radians per second}$

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3 years ago

at noon joice drove to the lake at 30 mi. per hour, but she made a long walk back at 4 mi. per hour. how long did she walk ifshe

Kryger [21]

Distance = 30 mph * time
distance = 4 mph * time

distance = 30 mph * t
distance = 4 mph * (17-t)

Since distance is equal then
30 mph * t = 4 mph * (17-t)

30t = -4t + 68

34t = 68

t = 2 hours

We see the return trip time is (17 -t ) which is 15 hours.
The beginning trip time is 2 hours.

Double Check
Beginning trip = 30 miles * 2 = 60 miles
Return trip = 4 miles * 15 = 60 miles.

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3 years ago

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kakasveta [241]

Answer:90

Step-by-step explanation:

My reasoning is because it makes a right angle and a right angle is equivalent to 90 degrees

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Answer:

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Step-by-step explanation:

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Answer:

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Step-by-step explanation:

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