All categories

3 years ago

What is the scientific notation of 0.00165?

Mathematics

1 answer:

Ierofanga [76]3 years ago

6 0

Answer:

The answer is $1.65*10^{-3}$

Step-by-step explanation:

when writing scientific notation, there must be one number to the left of the decimal point.

To achieve this in this problem, you need to move the decimal point 3 times to the right.

because you are moving the point to the right, the exponent will be negative.

*rule of thumb: moving the decimal to the left will give you a positive exponent, moving to the right will give you a negative exponent*

therefore you answer should be written as:

$1.65*10^{-3}$

hope this helps :)

You might be interested in

Rewrite with only sin x and cos x.

Annette [7]

Option A

$\cos 3 x=\cos x-4 \cos x \sin ^{2} x$

Solution:

Given that we have to rewrite with only sin x and cos x

Given is cos 3x

$cos 3x = cos(x + 2x)$

We know that,

$\cos (a+b)=\cos a \cos b-\sin a \sin b$

Therefore,

$\cos (x+2 x)=\cos x \cos 2 x-\sin x \sin 2 x$ ---- eqn 1

We know that,

$\sin 2 x=2 \sin x \cos x$

$\cos 2 x=\cos ^{2} x-\sin ^{2} x$

Substituting these values in eqn 1

$\cos (x+2 x)=\cos x\left(\cos ^{2} x-\sin ^{2} x\right)-\sin x(2 \sin x \cos x)$ -------- eqn 2

We know that,

$\cos ^{2} x-\sin ^{2} x=1-2 \sin ^{2} x$

Applying this in above eqn 2, we get

$\cos (x+2 x)=\cos x\left(1-2 \sin ^{2} x\right)-\sin x(2 \sin x \cos x)$

$\begin{aligned}&\cos (x+2 x)=\cos x-2 \sin ^{2} x \cos x-2 \sin ^{2} x \cos x\\\\&\cos (x+2 x)=\cos x-4 \sin ^{2} x \cos x\end{aligned}$

$\cos (x+2 x)=\cos x-4 \cos x \sin ^{2} x$

Therefore,

$\cos 3 x=\cos x-4 \cos x \sin ^{2} x$

Option A is correct

7 0

3 years ago

What 2 numbers multiply to -147 but add to -14?

Bezzdna [24]

Okay, so let's go over multiplying negative numbers. A positive times a positive is a positive, right? But a negative times a negative is also a positive. Only a negative times a positive (or a positive times a negative) gives you a negative number. So, we know that one of our 2 numbers in this question must be negative; the other must be positive.

Let's now take a look at the factors of -147, starting with the positives. Obviously, -147 and 1 are factors: -147 * 1 = -147. What other factors of -147 are there?

What about 7? Try it: -147 / 7 = -21. So here are two factors: -21, and 7. They multiply to -147. Do they add up to -14? Let's see: -21+7 = 7+(-21) = 7-21= -14. Yup, that works!

Answer: -21 and 7

4 0

3 years ago

Jake completed a marathon race in 3 hours and 12 minutes. What would be Jake's running time as a decimal?

VikaD [51]

$\text{Given that Jake completed a marathon race in 3 hours and 12 minutes.}\\
\\
\text{we need to find this time in decimals. so we will convert 12 minutes into hours}\\
\\
\text{We know that there are 60 minutes in 1 hour. }\\
\\
\text{so in 1 minute there will be}=\frac{1}{60 }\text{ hour}$

$\text{hence in 12 minutes we have}=\frac{1}{60}\times 12=\frac{1}{5}=0.2 \text{ hours}\\
\\
\text{hence the Jake's running time is}=3\text{hours + 12 minute}\\
\\
=3\text{ hours}+0.2 \text{ hours}\\
\\
=3.2 \text{ hours}$

Hence, Jake's running time in decimal is: 3.2 hours

4 0

3 years ago

Write your answer as a decimal or whole number. ___% of $75=$42

Basile [38]

Answer:

x=56

Step-by-step explanation:

$\frac{x}{100}$ · $\frac{42}{75}$

then cross multiply

4200=75x

x=56

3 0

3 years ago

(HELP ASAP PLEASE)

vlada-n [284]

Answer:

for four copies the cost is $72

Step-by-step explanation:

52 + 5a = 24 + 12a

28 + 5a = 12a

28 = 7a

a = 4

52 + 20 = 72

for four copies the cost is $72

6 0

3 years ago