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3 years ago

Evaluate 2x2 - 1 when x = 3.

Mathematics

2 answers:

myrzilka [38]3 years ago

7 0

When x is evaluated to 3 you get 11.

2(3)2-1 = 11

tigry1 [53]3 years ago

6 0

X should equal 11
2(3)2-1
6(2)-1
12-1
11

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5y − x =10 , solve the equation for y?

jek_recluse [69]

Answer:

-2

Step-by-step explanation:

7 0

2 years ago

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Find the product of z1 and z2, where z1 = 7(cos 40° + i sin 40°) and z2 = 6(cos 145° + i sin 145°).

Oduvanchick [21]

For two complex numbers $z_1=re^{i\theta}=r(\cos\theta+i\sin\theta)$ and $z_2=se^{i\varphi}=s(\cos\varphi+i\sin\varphi)$ , the product is

$z_1z_2=rse^{i(\theta+\varphi)}=rs(\cos(\theta+\varphi)+i\sin(\theta+\varphi))$

That is, you multiply the moduli and add the arguments. You have $z_1=7e^{i40^\circ}$ and $z_2=6e^{i145^\circ}$ , so the product is

$z_1z_2=7\times6(\cos(40^\circ+145^\circ)+i\sin(40^\circ+145^\circ)=42(\cos185^\circ+i\sin185^\circ)=42e^{i185^\circ}$

3 0

2 years ago

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How many seconds will light leaving Los Angeles take to reach the following locations (a) San Francisco (about 500km), (b) Londo

kondor19780726 [428]

Answer:

a) It takes 0.0017s for the light to reach San Francisco.

b) It takes 0.033s for the light to reach London.

c) It takes 1.334s for the light to reach Mars.

d) It takes 149.7s for the light to reach Venus.

Step-by-step explanation:

Here we can solve this problem by using this following formula:

$s = \frac{d}{t}$

In which s is the speed(in km/s), d is the distance(in km) and t is the time(in s).

The light speed is 299 792 458 m / s = 299,792.458 km/s, so $s = 299,792.458$

(a) San Francisco (about 500km)

Find t when $d = 500$ . So

$s = \frac{d}{t}$

$299,792.458 = \frac{500}{t}$

$299,792.458t = 500$

$t = \frac{500}{299,792.458}$

$t = 0.0017s$

It takes 0.0017s for the light to reach San Francisco.

b) London(about 10,000km)

Find t when $d = 10,000$ . So

$s = \frac{d}{t}$

$299,792.458 = \frac{10,000}{t}$

$299,792.458t = 10,000$

$t = \frac{10,000}{299,792.458}$

$t = 0.033s$

It takes 0.033s for the light to reach London.

(c) the Moon (400,000km)

Find t when $d = 400,000$ . So

$s = \frac{d}{t}$

$299,792.458 = \frac{400,000}{t}$

$299,792.458t = 400,000$

$t = \frac{400,000}{299,792.458}$

$t = 1.334s$

It takes 1.334s for the light to reach Mars.

(d) Venus (0.3 A.U. from Earth at its closest approach).

Each A.U. has 149,59,7871 km.

So 0.3 A.U. = 0.3*(149,597,871) = 44,879,361.3. This means that $d = 44,879,361.3$ . So:

$s = \frac{d}{t}$

$299,792.458 = \frac{44,879,361.3}{t}$

$299,792.458t = 44,879,361.3$

$t = \frac{44,879,361.3}{299,792.458}$

$t = 149.7s$

It takes 149.7s for the light to reach Venus.

3 0

3 years ago

Jacob consumes an energy drink that contains caffeine. After consuming the energy drink, the amount of caffeine in Jacob's body

sasho [114]

Answer: 0.87400mg of caffeine.

Step-by-step explanation:

You have

N(t)=N0(e^−rt)(1)

as a general Exponential decay equation where N0 is the amount at t=0, N(t) is the amount remaining at time t and r is the exponential decay constant. You're specifically given that after 10 hours, the decay factor is 0.2601, i.e.,

N(10)/N(0)=N0(e^−10r)/N0(e^0)= e^−10r=0.2601 . .(2)

Taking the last 2 parts of (2) to the power of 0.1t gives

e^−rt=0.2601^.1t . .(3)

This means that

N(t)=N0(e^−rt)=N0(0.2601^.1t). .(4)

Also,

N(2.56)N(1.56)=N0(0.2601.1(2.56))N0(0.2601.1(1.56))=0.2601.1(2.56−1.56)=0.2601^.1

= 0.87400mg of caffeine.

6 0

3 years ago

Which equation is graphed below?<br>A. y=2[x-3]<br>B. y=2[x]-3<br>C. y=[2x-3]<br>D. y2([x]-3)

kvasek [131]

I think it is C it is probably wrong ☹️

8 0

3 years ago