Question

Which of these sets of numbers contains no irrational numbers? (1 point) , , –8.15 ,

Answer 1

what sets?

Answer 2

square root -5 ,- square root 196 , –8.15 or square root -144, square root 49, 6.6 or -2. 3/8 square root 10, -0.6868... or -1, 5/6 square root 11


,

Answer 3

im really sorry, but thats still not very clear to me, are those negative signs? i want to help but i dont understand what the sets are

Answer 4

yes

Answer 5

so the first "set" is \[\sqrt{-5}\] ?

Answer 6

that and -196 and -8.15 then the others are separated by the word "or"

Answer 7

aah i see, ok i'll get on it

Answer 8

thank you

Answer 9

are you sure its
\[\sqrt{-5} \text{ instead of } -\sqrt{5}\]
because the first is a "complex" number, the square root of a negative

i'll continue anyway:
square root -5 ,- square root 196 , –8.15 :

\[\sqrt{-5} \text{ , } -\sqrt{196} \text{ , } -8.15 \]

a number is irrational if it cannot be written as a fraction

although the \[- \sqrt{196} = - \sqrt{14^2} = -14\]

which is rational,

\[\sqrt{-5} = i \sqrt{5}\]
which cannot be written as a fraction as the square root of 5 is a surd

Answer 10

are you sure there are all those negative signs? it seems a bit out of context compared with the rest of the question

Answer 11

\[-\sqrt{5}\]

Answer 12

that makes much more sense

Answer 13

sorry helping my son with this and I have never did this kind of math

Answer 14

no problem : )

i'll just write it out with the equation thingy, then i'll explain ->

square root -5 ,- square root 196 , –8.15 or square root -144, square root 49, 6.6 or -2. 3/8 square root 10, -0.6868... or -1, 5/6 square root 11 :

\[[ -\sqrt{5} , -\sqrt{196} , -8.15 ] \text{ , } [ -\sqrt{144}, \sqrt{49} , 6.6] , [-2,\frac{3}{8}\sqrt{10},-0.6868...] , [-1,\frac{5}{6} \sqrt{11} ]\]

Answer 15

ah a bit got cut off

Answer 16

i'll go ahead and do some explaining

in maths we have "rational numbers" which is a facy way of saying
"numbers that can be written as fractions"

"irrational numbers" are numbers that cant be written as fractions

any counting number, positive or negative, can be written as a fraction

eg \[1 = \frac{1}{1} \text{ , } 15 = \frac{15}{3} \text{ , } -6 = \frac{-6}{1}\]

other examples of rationals:

\[ \frac{3}{8} \text{ , } \frac{4}{10} \text{ , } \frac{22}{27}\]

Answer 17

some numbers we cannot write as fractions, for example

\[\sqrt{2} \] cannot be written as a fraction

Answer 18

oooooo ic thank you

Answer 19

here is a good video that may help:

http://www.youtube.com/watch?v=QIoVPtbEUjw

Answer 20

if we take a square root of a square number, that is rational

eg sqrt(4) = 2 = 2/1

Answer 21

sorry i made a mistake earlier, 15 = 15/1 not 15/3