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4 years ago

Item 10

Mathematics

1 answer:

vekshin14 years ago

7 0

Answer:

1.75

Step-by-step explanation:

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I need help ASAP pleaseee

Tanya [424]

Answer:Price of laptop A = $1220

Step-by-step explanation:

Sum of the price: A + B = 2185

Sum of the price: A + C = 2571

B : C = 5 : 7

B = 5/7 × C

So, replace the B:

A + 5/7 C = 2185

A + C = 2571

Eliminate by subtracting the first from the second: 2/7 C = 386

C = 1351

So, A = 2571 - 1351 = 1220

3 0

3 years ago

Integrate the following problem:

vazorg [7]

Answer:

$\displaystyle \frac{2 \cdot sin2x-cos2x}{5e^x} + C$

Step-by-step explanation:

The integration by parts formula is: $\displaystyle \int udv = uv - \int vdu$

Let's find u, du, dv, and v for $\displaystyle \int e^-^x \cdot cos2x \ dx$ .

$u=e^-^x$
$du=-e^-^x dx$

$dv=cos2x \ dx$
$v= \frac{sin2x}{2}$

Plug these values into the IBP formula:

$\displaystyle \int e^-^x \cdot cos2x \ dx = e^-^x \cdot \frac{sin2x}{2} - \int \frac{sin2x}{2} \cdot -e^-^x dx$
$\displaystyle \int e^-^x \cdot cos2x \ dx = \frac{e^-^x sin2x}{2} - \int \frac{sin2x}{2} \cdot -e^-^x dx$

Now let's evaluate the integral $\displaystyle \int \frac{sin2x}{2} \cdot -e^-^x dx$ .

Let's find u, du, dv, and v for this integral:

$u=-e^-^x$
$du=e^-^x dx$
$dv=\frac{sin2x}{2} dx$
$v=\frac{-cos2x}{4}$

Plug these values into the IBP formula:

$\displaystyle \int -e^-^x \cdot \frac{sin2x}{x}dx = -e^-^x \cdot \frac{-cos2x}{4} - \int \frac{-cos2x}{4}\cdot e^-^x dx$

Factor 1/4 out of the integral and we are left with the exact same integral from the question.

$\displaystyle \int -e^-^x \cdot \frac{sin2x}{x}dx = -e^-^x \cdot \frac{-cos2x}{4} + \frac{1}{4} \int cos2x \cdot e^-^x dx$

Let's substitute this back into the first IBP equation.

$\displaystyle \int e^-^x \cdot cos2x \ dx = \frac{e^-^x sin2x}{2} - \Big [ -e^-^x \cdot \frac{-cos2x}{4} + \frac{1}{4} \int cos2x \cdot e^-^x dx \Big ]$

Simplify inside the brackets.

$\displaystyle \int e^-^x \cdot cos2x \ dx = \frac{e^-^x sin2x}{2} - \Big [ \frac{e^-^x \cdot cos2x}{4} + \frac{1}{4} \int cos2x \cdot e^-^x dx \Big ]$

Distribute the negative sign into the parentheses.

$\displaystyle \int e^-^x \cdot cos2x \ dx = \frac{e^-^x sin2x}{2} - \frac{e^-^x \cdot cos2x}{4} - \frac{1}{4} \int cos2x \cdot e^-^x dx$

Add the like term to the left side.

$\displaystyle \int e^-^x \cdot cos2x \ dx + \frac{1}{4} \int cos2x \cdot e^-^x dx= \frac{e^-^x sin2x}{2} - \frac{e^-^x \cdot cos2x}{4}$
$\displaystyle \frac{5}{4} \int e^-^x \cdot cos2x \ dx = \frac{e^-^x sin2x}{2} - \frac{e^-^x \cdot cos2x}{4}$

Make the fractions have common denominators.

$\displaystyle \frac{5}{4} \int e^-^x \cdot cos2x \ dx = \frac{2e^-^x sin2x}{4} - \frac{e^-^x \cdot cos2x}{4}$

Simplify this equation.

$\displaystyle \frac{5}{4} \int e^-^x \cdot cos2x \ dx = \frac{2e^-^x sin2x - e^-^x cos2x}{4}$

Multiply the right side by the reciprocal of 5/4.

$\displaystyle \int e^-^x \cdot cos2x \ dx = \frac{2e^-^x sin2x - e^-^x cos2x}{4} \cdot \frac{4}{5}$

The 4's cancel out and we are left with:

$\displaystyle \int e^-^x \cdot cos2x \ dx = \frac{2e^-^x sin2x - e^-^x cos2x}{5}$

Factor $e^-^x$ out of the numerator.

$\displaystyle \int e^-^x \cdot cos2x \ dx = \frac{e^-^x(2 \cdot sin2x-cos2x)}{5}$

Simplify this by using exponential properties.

$\displaystyle \int e^-^x \cdot cos2x \ dx = \frac{2 \cdot sin2x-cos2x}{5e^x}$

The final answer is $\displaystyle \int e^-^x \cdot cos2x \ dx = \frac{2 \cdot sin2x-cos2x}{5e^x} + C$ .

7 0

3 years ago

Read 2 more answers

Ron and Harry both parked their cars at a parking lot. Ron parked his car for 8 hours at $3 per hour and Harry parked his car fo

SpyIntel [72]

Alright, so Ron parked his car for 8 hours at $3 per hour.

Harry parked his car for 7 hours at $3 per hour.

So, per day Ron is spending (8 * 3) = $24 a day
and Harry is spending ( 7 * 3 ) = $21 a day

So now solve for 5 days. 24 * 5 = $120 21 * 5 = $105

Add both together
$120
+
$105

=
Your Answer:
$225 altogether.

4 0

4 years ago

Read 2 more answers

ABCD is a rectangle. Find the length of segment AC

Oksana_A [137]

Answer:

Step-by-step explanation:

First, find x. As BE and DE will have the same measurements, you can set your formula up as

5x+11=3x+17

5x=3x+17-11

5x-2x=6

2x=6

x=6/2

x=3

CE and AE will also have the same value, now substitute 3 in place of x to get the value of segment BE

5x+11

5*3+11 = 26

This also means that CE = 26 and AE = 26

AC = CE + AE

AC = 52

4 0

3 years ago

Do these side lengths make a triangle?<br> 8 8 4

chubhunter [2.5K]

Answer:

Yes, isosceles triangle

Step-by-step explanation:

Side lengths of 8, 8, and 4 will make an isosceles triangle.

It would look something like this:

7 0

3 years ago

Read 2 more answers