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3 years ago

Which of the following is a complex number?2+ 34 9i

Mathematics

2 answers:

Tju [1.3M]3 years ago

8 0

Answer:

Option 3 - $4+9i$

Step-by-step explanation:

Given : Options in the figure.

To find : Which of the following is a complex number?

Solution :

Complex number is defined as the number which contains real number along with imaginary number.

The complex number is in the form of a+ib.

Now, we determine one by one.

Option 1 - -7

-7 is the real number not complex.

Option 2 - $2+\sqrt{3}$

$2+\sqrt{3}$ is the real number not complex.

Option 3 - $4+9i$

$4+9i$ is in the form a+ib so it is a complex number.

Option 4 - $\pi$

$\pi$ is the real number not complex.

Therefore, Only option 3 is the complex number.

Brut [27]3 years ago

4 0

4+9i, since i is a complex number which is the square root of 1. It is the only solution with i in it.

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An open box is to be made out of a 6-inch by 14-inch piece of cardboard by cutting out squares of equal size from the four corne

lawyer [7]

Answer:

The dimensions of the resulting box that has the largest volume is 1.3 inches x 1.3 inches

Step-by-step explanation:

Card board size is L= 14 inches and

W = 6 inches

Let x be the size of equal squares cut from 4 corners and bent into a box whose size is now;

L = 14 − 2x , W = 6 −2x and h = x inches.

Volume of the box is given as;

V = (14 −2x)(6−2x)x

V =(4x² − 40x + 84)x

= 4x³ − 40x² + 84x.

Now, for the maximum value,

dV/dx =0

Thus,

dv/dx = 12x² - 80x + 84 = 0

Using quadratic formula

x = [-(-80) ± √(-80²) - 4(12 x 84)]/(2 x 12)

x = [80 ± √(6400 - 4032)]/24

x = (80 + 48.66)/24 or (80-48.66)/24

x = 5.36 or 1.31

Looking at the two values, 1.31 would be more appropriate because if we use 5.36,we will get a negative value of the width (W).

Thus, x = 1.31 inches

Let us use the Second Derivative Test to verify that V has a local maximum at x = 1.31.

Thus;

d²v/dx² = 24x - 80 = 24(1.31) - 80 = -48.56

This is less than 0 and therefore, the volume of the box is maximized when a 1.31 inch by 1.3 inch square is cut from the corners of the cardboard sheet.

3 0

3 years ago

Solving quadratic equation using the completing method.<br>(a).x^2+6x+1=0

irina1246 [14]

Answer:

$x = -3 + 2\sqrt2 \ , \ x = -3 - 2\sqrt2$

Step-by-step explanation:

x² + 6x + 1 = 0

a = 1 , b = 6 , c = 1

$x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\\\\x = \frac{-6 \pm \sqrt{36-4}}{2}\\\\x=\frac{-6 \pm \sqrt{32}}{2}\\\\x= \frac{-6 \pm \sqrt{16 \times 2}}{2}\\\\x = \frac{-6 +4\sqrt2 }{2}\\\\x = -3 + 2\sqrt2 \ , \ x = -3 - 2\sqrt2$