soo. ive got to find the simpliest radical for a square root of -72.
My Answer: 5 square root 2
Corrrrect? *Finger crossed*.
i = sqrt(-1)
sqrt(-72) = sqrt(9 x 8 x (-1)) = sqrt(9x4x2x(-1)) = 3(2) i sqrt2 = 6i sqrt2
i = sqrt(-1)
sqrt(-72) = sqrt(9 x 8 x (-1)) = sqrt(9x4x2x(-1)) = 3(2) i sqrt2 = 6i sqrt2
Maybe with an extra step it will be clearer:
sqrt(-72) = sqrt(9 x 8 x (-1)) = sqrt (9 x 4 x 2 x (-1)) = sqrt(9) sqrt(4) sqrt(2) sqrt(-1) (remeber sqrt(-1) = i)
= (3) x (2) x sqrt(2) x i
= 6 i sqrt 2
Better? Maybe not......ha
gave me a little head ache! (: but yes, even though it is longer, when you added the extra step, it helps! i have an IEP.. and so umm, i cannot grasp things as fast as the avrage students, sadly. :(
Keep chipping away at it.....new stuff is always a bit confusing at first , but it will become easier. I didn't do very well in math in my early years, but eventually things 'clicked' and I graduated with honors from engineering school with little effort.
LOL......That just depends on your definition of 'young' vs 'old' There ARE people older than me! ha
lool! I am going to guess your in your mid to late 30's. i consider old to be 99+!
The easiest way to do it, is to break the number in question into its PRIME factors:
sqrt(-72)=sqrt(2 X 2 X 2 X 3 X 3 X -1). Now, for every pair of numbers you have INSIDE the bracket, select one of them OUTSIDE the bracket. So, we take one 2 X one 3=6. Out of three 2's, that leaves one 2 INSIDE the bracket. And, since sqrt(-1)=i, then we have: 6i sqrt(2).
