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3 years ago

22) Subtract (4 - 21) - (3 - 51) A) 1+3i B) 1-71 7+3i D) 7-7i

Mathematics

2 answers:

Natalka [10]3 years ago

5 0

Answer:

1 +3i

Step-by-step explanation:

(4 - 2i) - (3 - 5i)

Subtract the reals

4 - 3 =1

Subtract the imaginary

-2i - -5i

-2i + 5i = 3i

1 +3i

Firlakuza [10]3 years ago

3 0

Answer:

Step-by-step explanation:

Subtract all real numbers

4 - 3 = 1

Subtract all imaginary numbers

-2i - (-5i) = 3i

Put back together

1 + 3i

Best of Luck!

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3 years ago

3. There are 350 people in an office building. A local deli randomly surveyed people in the building to determine the average am

IrinaK [193]

Answer:

(a)Sample 1

The Mean = 20

The median = 25

Sample 2

The Mean = 31

The median = 60

(b) Sample 1 has the least spread

Sample 1 has the least deviations from the mean

The least representative of the population is sample 1

Step-by-step explanation:

The mean is ∑fx/∑f

∑fx = 30 + 25 + 10 + 25 + 10 = 100

∑f = 5

Mean = 100/5 = 20

For the median, we arrange the data in increasing order;

10, 10, 25, 25, 30

The median = the middle number = 25

Sample 2

The mean is ∑fx/∑f

∑fx = 5 + 60 + 10 + 30 + 50 = 155

∑f = 5

Mean = 155/5 = 31

For the median, we arrange the data in increasing order;

5, 10, 30, 50, 60

The median = the middle number = 30

(b) Sample 1 range =$30 -$10 = $20

Sample 2 range =$65 -$5 = $60

Sample 1 has the least spread

Sample 1 standard deviation = 9.354

Sample 2 standard deviation =24.083

Sample 1 has the least deviations from the mean

Mean = 24

$20, $20, $25, $25, $30

Median = $25

∑fx = 120

Therefore sample 1 align with the third sample

The least representative of the population is sample 1 with ∑fx = 100.

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3 years ago

10% of the 200 athletes at a lacrosse tournament have yellow jerseys. How many athletes have yellow jerseys?

mixas84 [53]

Answer:

20 athletes

Step-by-step explanation:

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2 years ago

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(5) Find the Laplace transform of the following time functions: (a) f(t) = 20.5 + 10t + t 2 + δ(t), where δ(t) is the unit impul

Aloiza [94]

Answer

(a) $F(s) = \frac{20.5}{s} - \frac{10}{s^2} - \frac{2}{s^3}$

(b) $F(s) = \frac{-1}{s + 1} - \frac{4}{s + 4} - \frac{4}{9(s + 1)^2}$

Step-by-step explanation:

(a) $f(t) = 20.5 + 10t + t^2 +$ δ(t)

where δ(t) = unit impulse function

The Laplace transform of function f(t) is given as:

$F(s) = \int\limits^a_0 f(s)e^{-st} \, dt$

where a = ∞

=> $F(s) = \int\limits^a_0 {(20.5 + 10t + t^2 + d(t))e^{-st} \, dt$

where d(t) = δ(t)

=> $F(s) = \int\limits^a_0 {(20.5e^{-st} + 10te^{-st} + t^2e^{-st} + d(t)e^{-st}) \, dt$

Integrating, we have:

=> $F(s) = (20.5\frac{e^{-st}}{s} - 10\frac{(t + 1)e^{-st}}{s^2} - \frac{(st(st + 2) + 2)e^{-st}}{s^3} )\left \{ {{a} \atop {0}} \right.$

Inputting the boundary conditions t = a = ∞, t = 0:

$F(s) = \frac{20.5}{s} - \frac{10}{s^2} - \frac{2}{s^3}$

(b) $f(t) = e^{-t} + 4e^{-4t} + te^{-3t}$

The Laplace transform of function f(t) is given as:

$F(s) = \int\limits^a_0 (e^{-t} + 4e^{-4t} + te^{-3t} )e^{-st} \, dt$

$F(s) = \int\limits^a_0 (e^{-t}e^{-st} + 4e^{-4t}e^{-st} + te^{-3t}e^{-st} ) \, dt$

$F(s) = \int\limits^a_0 (e^{-t(1 + s)} + 4e^{-t(4 + s)} + te^{-t(3 + s)} ) \, dt$

Integrating, we have:

$F(s) = [\frac{-e^{-(s + 1)t}} {s + 1} - \frac{4e^{-(s + 4)}}{s + 4} - \frac{(3(s + 1)t + 1)e^{-3(s + 1)t})}{9(s + 1)^2}] \left \{ {{a} \atop {0}} \right.$

Inputting the boundary condition, t = a = ∞, t = 0:

$F(s) = \frac{-1}{s + 1} - \frac{4}{s + 4} - \frac{4}{9(s + 1)^2}$

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3 years ago

The sum of a number and 4 is 6.5

ioda

Answer:

2.5

Step-by-step explanation:\

We can solve it like this

4 + x = 6.5

6.5 - 4 = x

6.5 - 4 = 2.5

4 + 2.5 = 6.5

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3 years ago

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