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3 years ago

Find the difference. (-2ab-2a-5) - (6ab+2)

Mathematics

1 answer:

9966 [12]3 years ago

4 0

Answer:

-8ab - 2a - 7

Step-by-step explanation:

Since you're subtracting/adding I like taking away the parentheses which makes the equation: -2ab - 2a - 5 - 6ab - 2

You combine like terms and get:

-8ab - 2a - 7

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Which of the following is the sum of the slopes of the line 3x+y=1 and a line perpendicular to this line? A 0 B 13 C −83 D −6

laiz [17]

Answer:

-8/3

Step-by-step explanation:

First find the slope of the line

3x+y = 1

Solve for y

y = -3x+1

This is in slope intercept form

y = mx+b where m is the slope

The slope is -3

The slopes of perpendicular lines multiply to -1

m* -3 = -1

m = 1/3

The line perpendicular has a slope of 1 / (3) = 1/3

The sum is -3 + 1/3

-9/2 + 1/3 = -8/3

3 0

3 years ago

Use Stokes' Theorem to evaluate C F · dr F(x, y, z) = xyi + yzj + zxk, C is the boundary of the part of the paraboloid z = 1 − x

Serggg [28]

I assume $C$ has counterclockwise orientation when viewed from above.

By Stokes' theorem,

$\displaystyle\int_C\vec F\cdot\mathrm d\vec r=\iint_S(\nabla\times\vec F)\cdot\mathrm d\vec S$

so we first compute the curl:

$\vec F(x,y,z)=xy\,\vec\imath+yz\,\vec\jmath+xz\,\vec k$

$\implies\nabla\times\vec F(x,y,z)=-y\,\vec\imath-z\,\vec\jmath-x\,\vec k$

Then parameterize $S$ by

$\vec r(u,v)=\cos u\sin v\,\vec\imath+\sin u\sin v\,\vec\jmath+\cos^2v\,\vec k$

where the $z$ -component is obtained from

$1-(\cos u\sin v)^2-(\sin u\sin v)^2=1-\sin^2v=\cos^2v$

with $0\le u\le\dfrac\pi2$ and $0\le v\le\dfrac\pi2$ .

Take the normal vector to $S$ to be

$\vec r_v\times\vec r_u=2\cos u\cos v\sin^2v\,\vec\imath+\sin u\sin v\sin(2v)\,\vec\jmath+\cos v\sin v\,\vec k$

Then the line integral is equal in value to the surface integral,

$\displaystyle\iint_S(\nabla\times\vec F)\cdot\mathrm d\vec S$

$=\displaystyle\int_0^{\pi/2}\int_0^{\pi/2}(-\sin u\sin v\,\vec\imath-\cos^2v\,\vec\jmath-\cos u\sin v\,\vec k)\cdot(\vec r_v\times\vec r_u)\,\mathrm du\,\mathrm dv$

$=\displaystyle-\int_0^{\pi/2}\int_0^{\pi/2}\cos v\sin^2v(\cos u+2\cos^2v\sin u+\sin(2u)\sin v)\,\mathrm du\,\mathrm dv=\boxed{-\frac{17}{20}}$

6 0

3 years ago

Math question I need help with

muminat

Let's you and me discuss a few things that you already know:

-- What's a y-intercept ?
The y-intercept on a graph is the place where it crosses the y-axis.

-- That's the value of 'x' at the y-intercept ?
The y-intercept is on the y-axis, so 'x' is zero there.

-- Good ! So how would you find the y-intercept of a function ?
You say that x=0 and look at what 'y' is.

-- Very nice. What's the function in this question ?
The function is

   f(x) [or 'y'] = x⁴ + 4x³ - 12x² -32x + 64 .

-- Excellent. What's the value oif that function (or 'y') when x=0 ?

   It's just 64 .

-- Beautiful.
   Are there any answer choices that cross the y-axis at 64 ?
   How many are there ?

   There's only one.
   It's the upper one on the right hand side.

3 0

3 years ago

A limited-edition poster increases in value each year with an initial value of $18. After 1 year and an increase of 15% per year

Roman55 [17]

Answer:

The required equation is $y = 18(1.15)^x$ .

Step-by-step explanation:

Consider the provided information.

The Initial value of poster = $ 18

After 1 year amount of increase = $ 20.70

With the rate of 15% = 0.15

Let future value is y and the number of years be x.

$y = 18(1.15)^x$

Now verify this by substituting x=1 in above equation.

$y = 18(1.15)^1=20.7$

Which is true.

Hence, the required equation is $y = 18(1.15)^x$ .

7 0

3 years ago

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Find the 31st term of the following sequence.. . 9, 15, 21, .... . . 186. 189. 195. . . is there an easy way to do this.

Alja [10]

This problem is an example of an arithmetic series.

The common difference of the second term (15) with the first term (9) and the third term (21) with the second term (15) [15-9=6; 21-15=6] is 6.

The formula for solving this is:
An= A1 +(n-1)*d where An is the nth term, A1 is the first term, n is the number of terms and d is the common difference.

An=9+ (31-1)*6 = 189

The answer is 189.

7 0

3 years ago

Read 2 more answers