Ask question

Ask question

All categories

2 years ago

13

The high temperature on a cold winter day was 20°F and the low temperature was –15°F. How much higher was the high temperature t

han the low temperature

1 answer:

marta [7]2 years ago

4 0

Answer:

The Temperature was 35 Degrees F higher than the low temperature.

Step-by-step explanation:

You might be interested in

Using polar coordinates, evaluate the integral which gives the area which lies in the first quadrant below the line y=5 and betw

vfiekz [6]

First, complete the square in the equation for the second circle to determine its center and radius:

<em>x</em> ² - 10<em>x</em> + <em>y</em> ² = 0

<em>x</em> ² - 10<em>x</em> + 25 + <em>y </em>² = 25

(<em>x</em> - 5)² + <em>y</em> ² = 5²

So the second circle is centered at (5, 0) with radius 5, while the first circle is centered at the origin with radius √100 = 10.

Now convert each equation into polar coordinates, using

<em>x</em> = <em>r</em> cos(<em>θ</em>)

<em>y</em> = <em>r</em> sin(<em>θ</em>)

Then

<em>x</em> ² + <em>y</em> ² = 100 → <em>r </em>² = 100 → <em>r</em> = 10

<em>x</em> ² - 10<em>x</em> + <em>y</em> ² = 0 → <em>r </em>² - 10 <em>r</em> cos(<em>θ</em>) = 0 → <em>r</em> = 10 cos(<em>θ</em>)

<em>y</em> = 5 → <em>r</em> sin(<em>θ</em>) = 5 → <em>r</em> = 5 csc(<em>θ</em>)

See the attached graphic for a plot of the circles and line as well as the bounded region between them. The second circle is tangent to the larger one at the point (10, 0), and is also tangent to <em>y</em> = 5 at the point (0, 5).

Split up the region at 3 angles <em>θ</em>₁, <em>θ</em>₂, and <em>θ</em>₃, which denote the angles <em>θ</em> at which the curves intersect. They are

<em>θ</em>₁ = 0 … … … by solving 10 = 10 cos(<em>θ</em>)

<em>θ</em>₂ = <em>π</em>/6 … … by solving 10 = 5 csc(<em>θ</em>)

<em>θ</em>₃ = 5<em>π</em>/6 … the second solution to 10 = 5 csc(<em>θ</em>)

Then the area of the region is given by a sum of integrals:

$\displaystyle \frac12\left(\left\{\int_0^{\frac\pi6}+\int_{\frac{5\pi}6}^{2\pi}\right\}\left(10^2-(10\cos(\theta))^2\right)\,\mathrm d\theta+\int_{\frac\pi6}^{\frac{5\pi}6}\left((5\csc(\theta))^2-(10\cos(\theta))^2\right)\,\mathrm d\theta\right)$

$=\displaystyle 50\left\{\int_0^{\frac\pi6}+\int_{\frac{5\pi}6}^{2\pi}\right\} \sin^2(\theta)\,\mathrm d\theta+\frac12\int_{\frac\pi6}^{\frac{5\pi}6}\left(25\csc^2(\theta) - 100\cos^2(\theta)\right)\,\mathrm d\theta$

To compute the integrals, use the following identities:

sin²(<em>θ</em>) = (1 - cos(2<em>θ</em>)) / 2

cos²(<em>θ</em>) = (1 + cos(2<em>θ</em>)) / 2

and recall that

d(cot(<em>θ</em>))/d<em>θ</em> = -csc²(<em>θ</em>)

You should end up with an area of

$=\displaystyle25\left(\left\{\int_0^{\frac\pi6}+\int_{\frac{5\pi}6}^{2\pi}\right\}(1-\cos(2\theta))\,\mathrm d\theta-\int_{\frac\pi6}^{\frac{5\pi}6}(1+\cos(2\theta))\,\mathrm d\theta\right)+\frac{25}2\int_{\frac\pi6}^{\frac{5\pi}6}\csc^2(\theta)\,\mathrm d\theta$

$=\boxed{25\sqrt3+\dfrac{125\pi}3}$

We can verify this geometrically:

• the area of the larger circle is 100<em>π</em>

• the area of the smaller circle is 25<em>π</em>

• the area of the circular segment, i.e. the part of the larger circle that is bounded below by the line <em>y</em> = 5, has area 100<em>π</em>/3 - 25√3

Hence the area of the region of interest is

100<em>π</em> - 25<em>π</em> - (100<em>π</em>/3 - 25√3) = 125<em>π</em>/3 + 25√3

as expected.

3 0

2 years ago

Inga [223]

Answer:

acute and obtuse

Step-by-step explanation:

the acute is less than 90 degrees and obtuse is more than 90 degrees

4 0

3 years ago

Help! im awful at these problems!!<br> solve the formula: t=v+k/g for g.

Sedbober [7]

Answer:

g = $\frac{k}{t-v}$

Step-by-step explanation:

Given

t = v + $\frac{k}{g}$

Multiply through by g to clear the fraction

tg = vg + k ( subtract vg from both sides )

tg - vg = k ← factor out g from each term on the left side

g(t - v) = k ← divide both sides by (t - v)

g = $\frac{k}{t-v}$

4 0

3 years ago

Will measures the distance around a tree using a tape measure as 48 inches. Use this measure to find the diameter of a cross sec

marin [14]

Answer: Assume the cross section is taken at the same height where the circumference was measured. Then

48/3 = 16 inches, close enough, actually. Trees aren't cylinders.

48 × 7 / 22 inches = 15.2727272

48/3.1415926 = 15.2788747

48/pi = 15.2788745368219522338128412837... ☺️

Step-by-step explanation:

circumference / diameter = pi = 3.1415926......

So diameter = circumference / pi.

6 0

3 years ago

Use scientific notation to estimate the number of inches in 1,225 miles. Include all calculations in your final answer. 1 inch ≈

mr_godi [17]

Answer:

7.763×10^7 inches

Step-by-step explanation:

$(1225\,mi)\dfrac{1\,in}{1.578\cdot 10^{-5}\,mi}=\dfrac{12.25}{1.578}\cdot 10^{2-(-5)}\,in \approx 7.763\cdot 10^7\,in$

When writing 1225 in scientific notation, it is convenient to choose an exponent so that the division result comes out with the right scale factor. It is easy to see that 1.2 < 1.6, so use of numbers with exactly one digit to the left of the decimal point would result in a fraction as an answer. We want the answer to have 1 digit left of the decimal point, so by scaling the operands to be 12. and 1.6, we get that result. Of course, the powers of 10 are adjusted accordingly.

This scaling process only matters if you're computing the results by hand. Any calculator can properly keep track of the required exponents.

__

"Back in the day" when slide rules were the calculating tool of choice, the operands and answer to any multiplication or division problem were only shown as 3 (sometimes 4) significant digits. All of the power-of-ten scaling was done "by hand" (usually, mentally). That is, the division would be 1225/1578 ≈ 776 × some scale factor. This is where thinking of the numbers as 12.25/1.578 = 7.76 comes in handy.

3 0

3 years ago