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3 years ago

4. Write the equation of line that is perpendicular to y= -1/3x + 7 and has a y intercept of -1.

Mathematics

1 answer:

jok3333 [9.3K]3 years ago

5 0

Answer:

Step-by-step explanation:

Two lines are perpendicular if the product of theirs slopes is equal -1:

y=m₁x+b₁ ⊥ y=m₂x+b₂ ⇒ m₁×m₂ = -1

y = -1/3x + 7 ⇒ m₁=-1/3

-1/3×m₂ = -1 ⇒ m₂ = 3

The y-intercept is b=-1 so the equation in slope-intercept form:

y = 3x - 1

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Element X decays radioactively with a half life of 12 minutes. If there are 200 grams of Element X, how long, to the nearest ten

Semenov [28]

Answer:

It would take 24 minutes for the element to decay to 50 grams

Step-by-step explanation:

The equation for the amount of the element present, after t minutes, is:

$Q(t) = Q(0)e^{-rt}$

In which Q(X) decays radioactively with a half life of 12 minutes.(0) is the initial amount and r is the rate it decreases.

Half life of 12 minutes

This means that $Q(12) = 0.5Q(0)$

$Q(t) = Q(0)e^{-rt}$

$0.5Q(0) = Q(0)e^{-12r}$

$e^{-12r} = 0.5$

$\ln{e^{-12r}} = \ln{0.5}$

$-12r = \ln{0.5}$

$12r = -\ln{0.5}$

$r = -\frac{\ln{0.5}}{12}$

$r = 0.05776$

If there are 200 grams of Element X, how long, to the nearest tenth of a minute, would it take the element to decay to 50 grams?

This is t when Q(t) = 50. Q(0) = 200.

$Q(t) = Q(0)e^{-rt}$

$50 = 200e^{-0.05776t}$

$e^{-0.05776t} = 0.25$

$\ln{e^{-0.05776t}} = \ln{0.25}$

$-0.05776t = \ln{0.25}$

$0.05776t = -\ln{0.25}$

$t = -\frac{\ln{0.25}}{0.05776}$

$t = 24$

It would take 24 minutes for the element to decay to 50 grams

6 0

4 years ago

Evaluate the following integral using trigonometric substitution

serg [7]

Answer:

The result of the integral is:

$\arcsin{(\frac{x}{3})} + C$

Step-by-step explanation:

We are given the following integral:

$\int \frac{dx}{\sqrt{9-x^2}}$

Trigonometric substitution:

We have the term in the following format: $a^2 - x^2$ , in which a = 3.

In this case, the substitution is given by:

$x = a\sin{\theta}$

$dx = a\cos{\theta}d\theta$

In this question:

$a = 3$

$x = 3\sin{\theta}$

$dx = 3\cos{\theta}d\theta$

$\int \frac{3\cos{\theta}d\theta}{\sqrt{9-(3\sin{\theta})^2}} = \int \frac{3\cos{\theta}d\theta}{\sqrt{9 - 9\sin^{2}{\theta}}} = \int \frac{3\cos{\theta}d\theta}{\sqrt{9(1 - \sin^{\theta})}}$

We have the following trigonometric identity:

$\sin^{2}{\theta} + \cos^{2}{\theta} = 1$

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

Replacing into the integral:

$\int \frac{3\cos{\theta}d\theta}{\sqrt{9(1 - \sin^{2}{\theta})}} = \int{\frac{3\cos{\theta}d\theta}{\sqrt{9\cos^{2}{\theta}}} = \int \frac{3\cos{\theta}d\theta}{3\cos{\theta}} = \int d\theta = \theta + C$

Coming back to x:

We have that:

$x = 3\sin{\theta}$

$\sin{\theta} = \frac{x}{3}$

Applying the arcsine(inverse sine) function to both sides, we get that:

$\theta = \arcsin{(\frac{x}{3})}$

The result of the integral is:

$\arcsin{(\frac{x}{3})} + C$

8 0

3 years ago

PLEASE HELP FOR BRAINLIEST

9966 [12]

Answer:

Mean is 70.2

Median is 72

Mode is 85

Step-by-step explanation:

The mean is the average

The medians the middle

The mode shows up the most

7 0

4 years ago

Please help me fist thank you

arsen [322]

Answer:

letter a

Step-by-step explanation:

3 0

3 years ago

Read 2 more answers

Which statements can be used to write an algebraic expression to represent the phrase? the quotient of a number and sixteen Chec

liubo4ka [24]

Answer:

t/16

•The correct algebraic expression is StartFraction t Over 16 EndFraction

Step-by-step explanation:

Quotient of a number and 16

Let the number=t

Quotient represent division

The expression can be written as t/16

•Replace "a number" with a variable, like t.

•Quotient represents division.

•The correct algebraic expression is StartFraction t Over 16 EndFraction

7 0

3 years ago