Question

how to solve this a^3>-1 and the answer is a<-1 , can anyone explain to me?

Answer 1

Yea!!

Answer 2

a^3 > -1
a > -1

Answer 3

cube toot of a is?

Answer 4

a^3>-1
a>-1

Answer 5

toot !? lol

Answer 6

take cube root on both sides.

Answer 7

the cube root of -1 is -1.

Answer 8

ull end up with -1 again hence the answer

Answer 9

no saif its -1

Answer 10

what nick?

Answer 11

saif said the same

Answer 12

-1^3=-1

Answer 13

Yea!

Answer 14

yes, it's cube root.
and i still confuse

Answer 15

or there is another way too
a^3 > -1
a^3 +1 > 0
(a + 1)(a^2 + 1 -a)> 0
^ ^
real complex

a >-1

Answer 16

a^3 > -1

a^3 + 1 > 0

(a+1)(a^2-a+1) > 0 .. factor with the sum of cubes formula

Since a^2-a+1 is ALWAYS positive (look at the graph of a^2-a+1 to see this or complete the square on a^2-a+1), this means that a^2-a+1 has NO influence on the sign of the entire expression.


So everything is dependent on the factor a+1


So because the entire expression is positive, and the sign depends on a+1, we know for sure that a+1 > 0


a+1 > 0
a > -1

So the solution is a > -1

Answer 17

but I am sure you don't want the complex thing so just so a>-1

Answer 18

make sure that there are no typos

Answer 19

Good Job Jim

Answer 20

okay, thank you all :)