2. The equation of a circle is x2 + y2 – 4x + 6y – 77 = 0.
a) Find the x-coordinates of the points A and B where the circle intersects the x-axis.
b) Find point of intersection of the tangents to the circle at A and B.​

Answers

Answer 1

a) The x-coordinates of the points A and B are [tex]x_{A} = 11[/tex] and [tex]x_{B} = -7[/tex].

b) The point of intersection of the tangents to the circle at A and B is [tex](x,y) = (2, 27)[/tex].

a) In this part we simplify the equation of the circle and solve for [tex]x[/tex] to determine the coordinates associated to the required points:

The coordinates of the two points so that circle intersects the x-axis, occurs when the following condition is met:

[tex]f(x, 0) = 0[/tex] (1)

Where [tex]f(x,y)[/tex] is in implicit form.

If we know that the equation of the circle is [tex]x^{2} + y^{2} - 4\cdot x + 6\cdot y - 77 = 0[/tex] and [tex]y = 0[/tex], then the reduced equation is:

[tex]x^{2} - 4\cdot x - 77 = 0[/tex] (2)

And we obtain the x-coordinates of the points by factoring (2):

[tex](x-11) \cdot (x + 7) = 0[/tex]

The x-coordinates of the points A and B are [tex]x_{A} = 11[/tex] and [tex]x_{B} = -7[/tex].

b) Lines are defined by both slope and intercept. Slope is defined by implicit differentiation and intercept is found by equation of the line.

Given that [tex]A(x,y) = (11, 0)[/tex] and [tex]B(x,y) = (-7, 0)[/tex], we determine line equations corresponding to each tangent line:

Slope

[tex]2\cdot x + 2\cdot y \cdot \dot y - 4 + 6\cdot \dot y = 0[/tex]

[tex](2\cdot y + 6)\cdot \dot y = 4 - 2\cdot x[/tex]

[tex]\dot y = \frac{2 - x}{y + 3}[/tex]

Point A

[tex]\dot y = \frac{2-11}{0 + 3}[/tex]

[tex]\dot y = -3[/tex]

Point B

[tex]\dot y = \frac{2-(-7)}{0 + 3}[/tex]

[tex]\dot y = 3[/tex]

Intercept

Point A ([tex]A(x,y) = (11, 0)[/tex], [tex]\dot y = -3[/tex])

[tex]b = y - m\cdot x[/tex]

[tex]b = 0 - (-3)\cdot (11)[/tex]

[tex]b = 33[/tex]

Point B ([tex]B(x,y) = (-7, 0)[/tex], [tex]\dot y = 3[/tex])

[tex]b = y - m\cdot x[/tex]

[tex]b = 0 - 3\cdot (-7)[/tex]

[tex]b = 21[/tex]

The equations of the lines tangent to the circle are:

[tex]y = -3\cdot x +33[/tex] (3)

[tex]y = 3\cdot x +21[/tex] (4)

The point of intersection is the solution of this system of linear equations:

[tex](x,y) = (2, 27)[/tex]

The point of intersection of the tangents to the circle at A and B is [tex](x,y) = (2, 27)[/tex].

We kindly invite you to see this question on circles: https://brainly.com/question/23988015


Related Questions

A king Palm can grow about 21 feet a year . Estimate the height of the kind palm , yard ,after 15 years

Answers

Answer:

10.5 yards after 15 years

Step-by-step explanation:

2.1 feet times 15 years, which equals to 31.5 feet, convert 31.5 feet into yards, so divide it by 0.3, and that equals to approximately 10.5 yards

Solve for x. 2x^2-4x=0
A.
0, -4
B.
0, -2
C.
0, 2
D.
2, 4

Answers

2x^2 - 4x = 0
2x(x - 2) = 0
Either x = 0 or x - 2 = 0
x = 0 or 2 so option C is correct

If $1000 is invested for 2 years with a 3% yearly interest rate. What is the amount of simple interest

Answers

Answer:

Total: 1060 Gain: 60

Step-by-step explanation:

1000 (Current Amount) x 0.03 (3% as a decimal) x 2 (year amount) = 60 + 1000 (Original Amount Invested) = 1060

Find the nth term for the following sequences, 100,96,90,82,72.(an^2+bn+c)​

Answers

9514 1404 393

Answer:

  t(n) = -n^2 -n +102

Step-by-step explanation:

We can use the first 3 terms to find a, b, c.

  a(1)^2 +b(1) +c = 100

  a(2)^2 +b(2) +c = 96

  a(3)^2 +b(3) +c = 90

Subtract the first equation from the other two:

  3a +b = -4 . . . . . . [eq4]

  8a +2b = -10 . . . . [eq5]

[eq5] can be reduced to

  4a +b = -5 . . . . . . [eq6]

Subtracting [eq4] from [eq6] gives ...

  (4a +b) -(3a +b) = (-5) -(-4)

  a = -1 . . . . . . . . simplify

Filling that into [eq4], we get

  3(-1) +b = -4

  b = -1 . . . . . . . add 3

Putting the values for 'a' and 'b' into the first equation gives ...

  -1 +-1 +c = 100

  c = 102

Then the n-th term t(n) of the sequence is ...

  t(n) = -n^2 -n +102

_____

Additional comment

As you might guess, there is a generic solution for quadratic sequences. In terms of the first term (a1), first first difference (d1), and second difference (d2), the coefficients can be written as ...

a = d2/2b = d1 -3ac = a1 -d1 +d2

This sequence has first differences of -4, -6, -8, -10, and second differences of -2. Putting the sequence values into the above formulas, we find ...

a = -2/2 = -1b = -4 -3(-1) = -1c = 100 -(-4) +(-2) = 102 . . . . . as above

Paul bought a student discount card for the bus. The card allows him to buy daily bus passes for $1.30. After one month, Paul bought 12 passes and spent a total of $22.60.

How much did he spend on the student discount card?

Answers

Answer:

$10.24

Step-by-step explanation:

12(1.30)=12.36

22.60-12.36=10.24

Help will give Brainly points

Answers

No they are not… not the same size

A contractor removed 357 cubi c ya rds of earth from a building site. If the contractor’s trucks can haul 17 cubic yards per load, how many truckloads of earth were moved?

Answers

Answer:

21 loads

Step-by-step explanation:

357/17=21

PLEASE HELP- brainliest and points will be given

Answers

Answer: Choice B

[tex]\frac{1}{\sqrt{65}}<-4, 7>[/tex]

===============================================================

Explanation:

Consider a right triangle with legs a = 4 and b = 7. Through the pythagorean theorem, the hypotenuse is

c = sqrt(a^2+b^2) = sqrt(4^2+7^2) = sqrt(65)

This represents the length of the vector <-4,7>

Dividing each component by the length will normalize the vector. This is the same as multiplying by [tex]\frac{1}{\sqrt{65}}[/tex] which is what choice B shows. The phrasing "normalize the vector" means "make the vector to be of length 1". A common application of normalizing vectors will come up in computer graphics.

The original vector and the vector mentioned in choice B point in the same direction. The only thing that has changed is the length from sqrt(65) to 1.

Can someone please help me please?

Answers

[tex] \large \mathfrak{Answer : }[/tex]

The equation of the red parabola is :

[tex]f(x) = 1 - {x}^{2} [/tex]

therefore , correct option in A

Evaluate the expression.
6(3 + 5)
26.
4
HELP

Answers

Answer =1267.2

Step-by-step explanation:

6(3+5)26.4

6×8×26.4

48×26.4

1267.2 is the answer

please help me answer this question.. am giving brainliest​

Answers

Step-by-step explanation:

We are going to use the following properties of logarithms to solve this problem:

[tex]\log{\dfrac{a}{b}} = \log{a} - \log{b}[/tex]

and

[tex]\log{ab} = \log{a} + \log{b}[/tex]

So we can rewrite the given equation as

[tex]\log{2x^3} - \log{x} = \log{\left(\dfrac{2x^3}{x}\right)} = \log{2x^2}[/tex]

Also,

[tex]\log{16} + \log{x} = \log{(16x)}[/tex]

So we can write

[tex]\log{2x^2} = \log{(16x)}[/tex]

or eliminating the log symbols, we get

[tex]2x^2 = 16x[/tex]

The solutions for the equation above are

[tex]x = 8\:\text{and}\: 0[/tex]

40 points please help

Answers

Answer:

[tex]\huge\boxed{-2}[/tex]

Step-by-step explanation:

Use any two points from the line.

Let them be:

(x1,y1) = (0,-2)

(x2,y2) = (-1,0)

Now,

[tex]\displaystyle Slope = \frac{y_2-y_1}{x_2-x_1} \\\\Slope = \frac{0-(-2)}{-1-0} \\\\Slope = \frac{2}{-1} \\\\Slope = -2\\\\\rule[225]{225}{2}[/tex]

Hope this helped!

~AH1807

Really need help quick

Answers

Answer:

Total Number of times Spun = 1200

Key sentence: "Pr(Red) is same as Pr(Yellow).

Pr(Green)= 0.2

0.2 = x/1200

x= 0.2 x 1200

x = 240.

It landed on green 240 times

Pr(Brown) =0.54

0.54 = y/1200

y= 1200 x 0.54

y= 648.

Now

To get the Number of times it landed on Red and Yellow

You simply subtract that of Green and Brown from 1200 and divide this result by 2(Since Red and Yellow are have equal occurrence).

1200 – (648 + 240)

= 312.

312/2 = 156.

So It landed on Red and Yellow 156 times each.

Step-by-step explanation:

Red ----- 156times

Green -----240times

Brown ----- 648times

Yellow -----156times

How do I write 680,705 in expanded form.

Answers

Answer:

600,000+80,000+700+5

Please help me and thank you!! Show the steps also please I got 198x

Answers

9514 1404 393

Answer:

  264x³-66x

Step-by-step explanation:

The order of operations requires this be evaluated as ...

  11x(96x÷4x -6) . . . . given

  11x(24x·x -6) . . . . . . division inside parentheses

  11x(24x² -6) . . . . . . multiplication inside parentheses

  264x³ -66x . . . . . multiply by outside factor (use the distributive property)

_____

Additional comment

The appearance of the expression in parentheses may induce you to evaluate it as (96x)÷(4x) = 24. The order of operations requires that you do the division before the multiplication, left to right, so this must be evaluated as ...

  ((96x)÷4)x = 24x²

You need to be very careful with division and with exponents to make sure to follow the Order of Operations exactly. If you have an appropriate calculator, it will do that automatically. For example, if you tell your calculator ...

  (for x=2) 11×2×(96×2÷4×2-6)

it should give you the result 1980, not 396.

Answer:

= 198x

Step-by-step explanation:

11x × { 96x ÷ 4x -6}

11x × { 24x -6}

264x - 66x

= 198x

You got the correct answer

Find the distance between the pair of points A(7,8) B(-8,4)

Answers

Answer:

Formula:

[tex]length = \sqrt{ {(x _{1} -x_{2} )}^{2} + {(y_{1} -y_{2}) }^{2} } [/tex]

substitute:

[tex]l = \sqrt{ { \{7 - ( - 8) \}}^{2} + {(8 - 4)}^{2} } \\ \\ l = \sqrt{225 + 16} \\ l = \sqrt{241} \\ { \boxed{ \boxed{length = 15.5 \: units}}}[/tex]

Find A in degrees C= 120° b= 5 c= 11

Answers

Answer:

36.8

Step-by-step explanation:

I think A=36.8

Hope it will help you (:

435 divided by 15 equals what?

Answers

The answer is 29 hope this helps :D

A triangle with a perimeter of 30 inches has sides of x+3, 2x+5, and x. find the value of x

Answers

Answer:

x = 5.5 inches.

Step-by-step explanation:

The perimeter is the sum of the 3 sides, so:-

x + x + 3 + 2x + 5 = 30

4x + 8 = 30

4x = 22

x = 5.5.

PLEASE HELP!!! How does the multiplicity of a zero affect the graph of the polynomial function?

Answers

9514 1404 393

Answer:

2, 4, 61cross

Step-by-step explanation:

Consider a zero at x=1.

If it has multiplicity 1, the corresponding factor is (x -1). Now consider the sign of that factor for x = 1.1. The value is (1.1 -1) = 0.1, a positive number.

When the value of x is 0.9, the factor is (0.9 -1) = -0.1, a negative number.

This tells you that values to the left of a zero make the factor(s) associated with that zero be negative. For x-values to the right of the zero, the factor(s) will be positive.

If the multiplicity is even, the product of those factors is positive on either side of the zero. (A negative number to an even power is a positive number.) That is, the graph will not change sign from one side of an even-multiplicity factor to the other. At an odd-multiplicity factor, the graph changes sign.

__

For the problem at hand, the only even-multiplicity factor is (x -1), so the graph will not change sign at x=1. It will touch the axis (be tangent to the x-axis), but will not cross. The other zeros have odd multiplicity (1 or 3), so the graph will change sign there.

It is worthwhile to note that the higher the multiplicity, the "flatter" the graph is at the zero. You can see this in the attachment by comparing the shape of the graph at x=6 with the shape at x=2 (also an upward zero crossing).

_____

Additional comment

You may wonder why the curve is below the x-axis at x=1 when the product of the factors in that neighborhood is always positive. The reason is that there are an odd number of zeros to the right of x=1, so the product of those factors is negative.

Match the expression to its value.
104
1
= 0.01
102
104
102
10,000
10-4. 102
1
= 0.000001
109
10-4
1
= 0.0001
10-

Answers

Answer:

Ans; 10⁴ —> 10, 000

Ans; 10-⁴ / 10² —> 1/ 10⁶ = 0. 000 001

Ans; 10-⁴ × 10² —> 1/ 10² = 0.01

Ans; 10-⁴ —> 1/ 10⁴ = 0. 000 1

I hope I helped you^_^

Answer:

A=a

B=d

C=c

D=b

Step-by-step explanation:

Solve for x: x^2+4b=0

Answers

Answer:

[tex] {x}^{2} + 4b = 0 \\ {x}^{2} = - 4b \\ x = \sqrt{ - 4b} \\ x = 2 \sqrt{b} i \\ thank \: you[/tex]

write 3.777777777 as a mixed number

Answers

The answer is 3 7/10
The above answer is wrong, it would be 3 and 7/9 because it is a repeating decimal.

Liliana has $2.10 in nickels and quarters in her backpack. She has 12 more nickels than quarters. How many coins of each type does she have?

Answers

Step-by-step explanation:

17 nickels and 5 quarters I just thought way to much for such a simple question

A cab company charges $3 per cab ride,
plus an additional $2 per mile driven. How
long is a cab ride that costs $11?
miles

Answers

The answers should be 4 miles

Answer:

The answer is c = 2 + 3d .

Step-by-step explanation:

It is given that a cab ride cost $2 which is a fixed amount and charges additional $3 per mile. So you have to make an equation of c in terms of d :

Let c be the cost,

Let d be the distance,

c = 2 + 3d

Evaluate u + xy, if u = 18, x = 10, and y = 8

Answers

Answer:

[tex]u + xy \\ 18 + 10 \times 8 \\ 10 + 80 \\ 90[/tex]

Answer:

Solution,

here,

u=18

x =10

y= 8

=u+xy

=18+(10×8)

=18+80

=98

3) A bullet travels 2400 feet per second. Write this in miles per hour, rounded to the nearest
whole mile per hour. Reference: 1 mile = 5280 feet

Answers

Answer:

1636mi/hr

Step-by-step explanation:

2400ft/s = _______mi/hr                   1 hr = 3600s          1mi = 5280ft

2400ft/s   x   3600s/hr   x   1mi/5280ft = 1636mi/hr

what is statistics ???
explain !!!​

Answers

Answer:

what is statistics ???

explain !!!

Step-by-step explanation:

Statistics is the science concerned with developing and studying methods for collecting, analyzing, interpreting and presenting empirical data. ... Probability is a mathematical language used to discuss uncertain events and probability plays a key role in statistics.Please mark me as brainliest

inductive reason what is next number in sequence 400, 200, 300, 150, 250​

Answers

Answer:

125

Step-by-step explanation:

400÷2 = 200

300÷2 = 150

so,

250÷2 = 125

A hotel has a total of 7 floors if there are 35 standard rooms on each floor how many standard rooms are there

Answers

There would 245 standard rooms

Answer:

245

Step-by-step explanation:

multiple the amount of rooms on each floor (35) by the amount of floors (7)

35x7=245 rooms

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