00:00Welcome everyone. So yes, a lot of people thought that the answer for this one was supposed to be 6.
00:05See, root of negative 4 and root of negative 9. We do it this way. We can club them, right?
00:12So this becomes root of 36. Negative into negative is positive.
00:16So for root of a positive value is always positive. So that should be 6.
00:21This is actually not wrong. But in roots, especially in roots,
00:26if we have a negative 1, root of a negative 1, that value is associated as an imaginary value which is called as i.
00:35So root of negative 4 can be written as root of 4 multiplied by root of minus 1
00:44which can be written as what? 2i, root of 4 is 2 and root of negative 1 is minus, sorry, root of negative 1 is i.
00:54Similarly, root of negative 9 can be written as root of 9 multiplied by root of minus 1 which is 3i.
01:03So this question has now changed to 2i multiplied by 3i.
01:08So here what happens is we have 6i square.
01:12Now what is i square? Squaring this, i square, I get it as what?
01:16root of negative 1, root of negative 1, the whole square.
01:21So i square is equals to minus 1.
01:30So here we will say 6 multiplied by minus 1.
01:33Answer for this question is minus 6.
01:35I hope this is very very clear to everyone.
01:38That's it for today. I will see you in the next video.
01:41Bye.
Comments