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

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saifoo.khanBest ResponseYou've already chosen the best response.0
take cube root on both sides.
 2 years ago

saifoo.khanBest ResponseYou've already chosen the best response.0
the cube root of 1 is 1.
 2 years ago

hahdBest ResponseYou've already chosen the best response.0
ull end up with 1 again hence the answer
 2 years ago

dinainjuneBest ResponseYou've already chosen the best response.0
yes, it's cube root. and i still confuse
 2 years ago

Ishaan94Best ResponseYou've already chosen the best response.0
or there is another way too a^3 > 1 a^3 +1 > 0 (a + 1)(a^2 + 1 a)> 0 ^ ^ real complex a >1
 2 years ago

jim_thompson5910Best ResponseYou've already chosen the best response.0
a^3 > 1 a^3 + 1 > 0 (a+1)(a^2a+1) > 0 .. factor with the sum of cubes formula Since a^2a+1 is ALWAYS positive (look at the graph of a^2a+1 to see this or complete the square on a^2a+1), this means that a^2a+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
 2 years ago

Ishaan94Best ResponseYou've already chosen the best response.0
but I am sure you don't want the complex thing so just so a>1
 2 years ago

jim_thompson5910Best ResponseYou've already chosen the best response.0
make sure that there are no typos
 2 years ago

dinainjuneBest ResponseYou've already chosen the best response.0
okay, thank you all :)
 2 years ago
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