Which expression is correct for question 7

Mathematics

1 answer:

Neko [114]3 years ago

5 0

◆ COMPLEX NUMBERS ◆

$given \: expression \: is \: - \\ \\ - 3 {i}^{4} + 2 {i}^{3} + 2 {i}^{2} + \sqrt{ - 9} \\ \\ we \: know \: that \: , \: \\ i = \sqrt{ - 1} \\ \\ {i}^{2} = - 1 \\ \\ {i}^{3 } = - i \\ \\ {i}^{4} = 1 \\ \\ \\ - 3 {i}^{4} + 2 {i}^{3} + 2 {i}^{2} + \sqrt{9} i \\ = - 3 {i}^{4} + 2 {i}^{3} + 2 {i}^{2} + 3i \\ \\ using \: the \: above \: properties \: of \: iota \: (i) \\ \\ = - 3(1) + 2( - i) + 2( - 1) + 3i \\ \\ = - 3 - 2i - 2 + 3i \\ \\ = (- 5 + i) \: \: \: ans.$

You might be interested in

I need help on this ASAP!!

vazorg [7]

The answer is 16 units
An easy way to find the perimeter is remembering the formula of a+b+c.
So in this case, you count how many units each line of the triangle it covers. 4+6+6= 16

7 0

2 years ago

Solve: 6 – x = 4(5 + x) – 4

frez [133]

Answer:

x= -2

Step-by-step explanation:

3 0

2 years ago

20 points!!!!!!!

castortr0y [4]

See the attached figure to better understand the problem
let
L-----> length side of the cuboid
W----> width side of the cuboid
H----> height of the cuboid

we know that
One edge of the cuboid has length 2 cm-----> I'll assume it's L
so
L=2 cm
[volume of a cuboid]=L*W*H-----> 2*W*H
40=2*W*H------> 20=W*H-------> H=20/W------> equation 1

[surface area of a cuboid]=2*[L*W+L*H+W*H]----->2*[2*W+2*H+W*H]

100=2*[2*W+2*H+W*H]---> 50=2*W+2*H+W*H-----> equation 2
substitute 1 in 2
50=2*W+2*[20/W]+W*[20/W]----> 50=2w+(40/W)+20
multiply by W all expresion
50W=2W²+40+20W------> 2W²-30W+40=0

using a graph tool------> to resolve the second order equation
see the attached figure

the solutions are
13.52 cm x 1.48 cm
so the dimensions of the cuboid are
2 cm x 13.52 cm x 1.48 cm
or
2 cm x 1.48 cm x 13.52 cm

Find the length of a diagonal of the cuboid
diagonal=√[(W²+L²+H²)]------> √[(1.48²+2²+13.52²)]-----> 13.75 cm

the answer is
the length of a diagonal of the cuboid is 13.75 cm