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2 years ago

HELPP

Mathematics

1 answer:

Agata [3.3K]2 years ago

8 0

Answer: The answer is Choice B.

Step-by-step explanation:

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How do i solve this help asap

shepuryov [24]

9/72

I forgot how to do this

6 0

3 years ago

Chistopher is 20 years younger than ishaan. Ishaan and chistopher first met two years ago. Fourteen years ago, ishaan was 3 time

lisabon 2012 [21]

Answer:

Ishaan is 49 years old.

Step-by-step explanation:

Let the present age of Christopher be 'C'.

Let the present age of Ishaan be 'I'.

From the given data, we can form equations which will help us solve the problem.

Christopher is 20 years younger than Ishaan. This means:

C = I - 20 . . . (1)

Fourteen years ago, Ishaan would have been (I -14) years old and Christopher (C - 14) years old.

From the data, I - 14 = 3(C - 14) . . . (2)

Substituting the value of C in Equation 2, we get:

I - 14 = 3(I - 20 - 14)

⇒ I - 14 = 3(I - 34)

⇒ I - 14 = 3I - 112

⇒ 2I = 112 + 14 = 98

⇒ I = 49

So, Ishaan is 49 years old.

4 0

3 years ago

Solve y ' ' + 4 y = 0 , y ( 0 ) = 2 , y ' ( 0 ) = 2 The resulting oscillation will have Amplitude: Period: If your solution is A

Vlad [161]

Answer:

$y(x)=sin(2x)+2cos(2x)$

Step-by-step explanation:

$y''+4y=0$

This is a homogeneous linear equation. So, assume a solution will be proportional to:

$e^{\lambda x} \\\\for\hspace{3}some\hspace{3}constant\hspace{3}\lambda$

Now, substitute $y(x)=e^{\lambda x}$ into the differential equation:

$\frac{d^2}{dx^2} (e^{\lambda x} ) +4e^{\lambda x} =0$

Using the characteristic equation:

$\lambda ^2 e^{\lambda x} + 4e^{\lambda x} =0$

Factor out $e^{\lambda x}$

$e^{\lambda x}(\lambda ^2 +4) =0$

Where:

$e^{\lambda x} \neq 0\\\\for\hspace{3}any\hspace{3}\lambda$

Therefore the zeros must come from the polynomial:

$\lambda^2+4 =0$

Solving for $\lambda$ :

$\lambda =\pm2i$

These roots give the next solutions:

$y_1(x)=c_1 e^{2ix} \\\\and\\\\y_2(x)=c_2 e^{-2ix}$

Where $c_1$ and $c_2$ are arbitrary constants. Now, the general solution is the sum of the previous solutions:

$y(x)=c_1 e^{2ix} +c_2 e^{-2ix}$

Using Euler's identity:

$e^{\alpha +i\beta} =e^{\alpha} cos(\beta)+ie^{\alpha} sin(\beta)$

$y(x)=c_1 (cos(2x)+isin(2x))+c_2(cos(2x)-isin(2x))\\\\Regroup\\\\y(x)=(c_1+c_2)cos(2x) +i(c_1-c_2)sin(2x)\\$

Redefine:

$i(c_1-c_2)=c_1\\\\c_1+c_2=c_2$

Since these are arbitrary constants

$y(x)=c_1sin(2x)+c_2cos(2x)$

Now, let's find its derivative in order to find $c_1$ and $c_2$

$y'(x)=2c_1 cos(2x)-2c_2sin(2x)$

Evaluating $y(0)=2$ :

$y(0)=2=c_1sin(0)+c_2cos(0)\\\\2=c_2$

Evaluating $y'(0)=2$ :

$y'(0)=2=2c_1cos(0)-2c_2sin(0)\\\\2=2c_1\\\\c_1=1$

Finally, the solution is given by:

$y(x)=sin(2x)+2cos(2x)$

5 0

3 years ago

Joey traveled 150 miles in 212 hours. Which expression gives Joey's speed in miles per hour?

Svetradugi [14.3K]

Answer:

0.7 miles per hour

Step-by-step explanation:

To find a speed in miles per hour, divide the number of miles by the number of hours.

150/ 212 = 0.7 miles per hour

4 0

2 years ago

3 sin(x) + 3 = sin(x)

kumpel [21]

Answer:

no solution

Step-by-step explanation:

3 sin x+3=sin x

3 sin x-sin x=-3

2 sin x=-3

sin x=-3/2

which is impossible as |sin x|≤ 1

8 0

2 years ago