Introduction to Cube Root - Quantitative Aptitude Video Lecture | Quantitative Aptitude (Quant) - CAT

let us look at what our cube roots in
this video a cube root is denoted by
this symbol and for example if you take
the cube root of 8 you get as to the
cube root of 8 is 2 the reason is if you
take the cube of 2 you get 8 so if you
write 2 times 2 times 2 you get 8 so
here it is the cube of 2 and 2 is the
cube root of 8
unlike square roots you can take the
cube root of negative numbers and it
comes out as the real number so the cube
root of minus 8 is what is the number
that when multiplied by itself size
gives you minus it well it turns out to
be minus 2 well let us write it here
minus 2 times minus 2 times minus 2 is
minus 8 minus 2 times minus 2 is 4 and 4
times minus 2 is minus 8 so the cube
root of 8 is minus 2 let us now look at
some of the properties of cube roots the
first two properties say that the cube
root of positive numbers is positive and
the cube root of negative numbers is
negative so if I have the cube root of
minus 1 it is minus 1 or if I have the
cube root of minus 27 it is minus 3 so 3
s cube is 27 minus 3 skew is minus
tradition hence the cube root of minus
27 is minus 3 let's go on to the next
property and it applies to all
exponential expressions so if you have a
is equal to the cube root the cube root
of x you can always write a cube is
equal to X so if you have cube root of
27 is equal to 3 you can take the cube
on both sides of the equal to so so
you have 27 is equal to 3 Q and of
course 27 is equal to 27 so this is how
you solve cube roots