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2 years ago

7a = 28 Is a=21 a solution? yes or no

Mathematics

2 answers:

bagirrra123 [75]2 years ago

4 0

No, because 7 x 21 is 147.

vovangra [49]2 years ago

3 0

Answer:

Step-by-step explanation:

No because if a = 21, then 7 * 21 = 147 and 147 is not 28.

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Solve for q (Please show all work thank you:))

Masja [62]

Answer:

q = ± $\frac{5}{4\sqrt{p} }$

Step-by-step explanation:

We are to solve for q in:

16pq² = 25

q² = $\frac{25}{16p}$

$\sqrt{q^2}$ = ± $\sqrt{\frac{25}{16p} }$ = ± $\frac{5}{4\sqrt{p} }$

5 0

2 years ago

Write down the explicit solution for each of the following: a) x’=t–sin(t); x(0)=1

Kay [80]

Answer:

a) x=(t^2)/2+cos(t), b) x=2+3e^(-2t), c) x=(1/2)sin(2t)

Step-by-step explanation:

Let's solve by separating variables:

$x'=\frac{dx}{dt}$

a) x’=t–sin(t), x(0)=1

$dx=(t-sint)dt$

Apply integral both sides:

$\int {} \, dx=\int {(t-sint)} \, dt\\\\x=\frac{t^2}{2}+cost +k$

where k is a constant due to integration. With x(0)=1, substitute:

$1=0+cos0+k\\\\1=1+k\\k=0$

Finally:

$x=\frac{t^2}{2} +cos(t)$

b) x’+2x=4; x(0)=5

$dx=(4-2x)dt\\\\\frac{dx}{4-2x}=dt \\\\\int {\frac{dx}{4-2x}}= \int {dt}\\$

Completing the integral:

$-\frac{1}{2} \int{\frac{(-2)dx}{4-2x}}= \int {dt}$

Solving the operator:

$-\frac{1}{2}ln(4-2x)=t+k$

Using algebra, it becomes explicit:

$x=2+ke^{-2t}$

With x(0)=5, substitute:

$5=2+ke^{-2(0)}=2+k(1)\\\\k=3$

Finally:

$x=2+3e^{-2t}$

c) x’’+4x=0; x(0)=0; x’(0)=1

Let $x=e^{mt}$ be the solution for the equation, then:

$x'=me^{mt}\\x''=m^{2}e^{mt}$

Substituting these equations in c)

$m^{2}e^{mt}+4(e^{mt})=0\\\\m^{2}+4=0\\\\m^{2}=-4\\\\m=2i$

This becomes the solution m=α±βi where α=0 and β=2

$x=e^{\alpha t}[Asin\beta t+Bcos\beta t]\\\\x=e^{0}[Asin((2)t)+Bcos((2)t)]\\\\x=Asin((2)t)+Bcos((2)t)$

Where A and B are constants. With x(0)=0; x’(0)=1:

$x=Asin(2t)+Bcos(2t)\\\\x'=2Acos(2t)-2Bsin(2t)\\\\0=Asin(2(0))+Bcos(2(0))\\\\0=0+B(1)\\\\B=0\\\\1=2Acos(2(0))\\\\1=2A\\\\A=\frac{1}{2}$

Finally:

$x=\frac{1}{2} sin(2t)$

7 0

3 years ago

What is the simplified fraction of 30/48 using the giant one

STatiana [176]

Answer:

The answer is

$\frac{30}{48} = \frac{15}{24}$

4 0

2 years ago

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zloy xaker [14]

Answer:

f(x) = 3^x increases steadily on the interval [4,5].

Step-by-step explanation:

This exponential function f(x) = 3^x has a positive base (3) which is larger than 1. Thus, this function continues to increase as x increases, including the case where x increases from 4 to 5.

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3 years ago

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Vilka [71]

Not sure!!!!!;( next time put a pic

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3 years ago