Christopher is analyzing a circle, y^2 + x^2 = 121, and a linear function g(x). Will they intersect?

Mathematics

1 answer:

Sav [38]3 years ago

7 0

Circle: x^2+y^2=121=11^2 => circle with radius 11 and centred on origin.
g(x)=-2x+12 (from given table, find slope and y-intercept)
We can see from the graphics that g(x) will be almost tangent to the circle at (0,11), and that both intersection points will be at x>=11.
To show that this is the case,
substitute g(x) into the circle
x^2+(-2x+12)^2=121
x^2+4x^2-2*2*12x+144-121=0
5x^2-48x+23=0
Solve using the quadratic formula,
x=(48 &pm; √ (48^2-4*5*23) )/10
=0.5058 or 9.0942
So both solutions are real and both have positive x-values.

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Write the complex number in polar form:

emmasim [6.3K]

9514 1404 393

Answer:

2√30 ∠-120°

Step-by-step explanation:

The modulus is ...

√((-√30)² +(-3√10)²) = √(30 +90) = √120 = 2√30

The argument is ...

arctan(-3√10/-√30) = arctan(√3) = -120° . . . . a 3rd-quadrant angle

The polar form of the number can be written as ...

(2√30)∠-120°

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<em>Additional comments</em>

Any of a number of other formats can be used, including ...

(2√30)cis(-120°)

(2√30; -120°)

(2√30; -2π/3)

2√30·e^(i4π/3)

Of course, the angle -120° (-2π/3 radians) is the same as 240° (4π/3 radians).

At least one app I use differentiates between (x, y) and (r; θ) by the use of a semicolon to separate the modulus and argument of polar form coordinates. I find that useful, as a pair of numbers (10.95, 4.19) by itself does not convey the fact that it represents polar coordinates. As you may have guessed, my personal preference is for the notation 10.95∠4.19. (The lack of a ° symbol indicates the angle is in radians.)

6 0

3 years ago

Two points in the Cartesian plane are A(2.00 m, −4.00 m) and B(−3.00 m, 3.00 m). Find the distance between them and their polar

Brrunno [24]

The distance between the two points is $d=8.6m$