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Feb 4 2014 01:58am
please work:

square root -8 times ( square root of -3 minus square root of -5)
I'm getting wrong answer.

<-8 ( <-3 - <-5)

< -8 x (-3) = < 24

< -8 x <-5 = 40

< 24-40 = < -16

i <16

not the right answer. I used < to symbolize square root.
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Feb 4 2014 02:19am
you left out sqrt root on the 40
and you cant do sqrt(a-b) = sqrt(a) -sqrt(b)
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Feb 4 2014 03:50am


worst notation ever

bonus points:
  • starts as an expression
  • becomes an equation
  • becomes an expression
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Feb 4 2014 04:20am
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Feb 4 2014 04:23am
Quote (fingerling @ 4 Feb 2014 07:58)
please work:

square root -8  times ( square root of -3 minus square root of -5)
I'm getting wrong answer.

<-8 ( <-3 - <-5)

< -8  x (-3) = < 24

< -8 x <-5 = 40

< 24-40 = < -16

i <16

not the right answer. I used < to symbolize square root.


do you mean sqrt(-8*[sqrt(-3)-sqrt(-5)]) ?

in that case you would start with sqrt(-8*[i*sqrt(3)-i*sqrt(5)])=sqrt(-8*i*(-1)*[sqrt(5)-sqrt(3)])=sqrt(8)*sqrt(i)*[sqrt(5)-sqrt(3)]

now you have the identiy sqrt(i)=[sqrt(2)/2]*(1+i) with sqrt(8)=sqrt(2)*2 you can simplify to

2*(1+i)*[sqrt(5)-sqrt(3)

and i leave the rest to you
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