Maths help
- Thread starter mattux
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X2 + 1 = 0 ??
the 2 should be little and on top but not sure how to do that
Its imaginary
X2 + 1 = 0 ??
the 2 should be little and on top but not sure how to do that
What does x^2 mean?
It means x squared or x multiplied by itself.
1^2 = 1
2^2 = 4
3^2 = 9
etc.
So what multiplied by itself equals -1?
Its imaginary
Pfft, youre imaginary.
If you put -1 times -1 in a calculator you will get 1.
A negative number multiplied by a negative number is positive.
Associate
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(-1)*(-1) = 1
The actual answer to x^2 = -1 is x = +/- i where i is the imaginary number (i = sqrt(-1)). But don't worry about it, if you're daughter is only doing simple linear equations at the moment then complex numbers are quite a way off yet
Sorry I was trying to get you to think about it fundumentally.
Assuming your daughter is in an early year in secondary school, it is supposed to be something to think about. The question has no real answer.
Your daughter should hopefully work that out on her own and be able to explain why.
As Physicsman said above, because it doesn't have a real answer, we make up an imaginary number called i to answer it.
(-1)*(-1) = 1
The actual answer to x^2 = -1 is x = +/- i where i is the imaginary number (i = sqrt(-1)). But don't worry about it, if you're daughter is only doing simple linear equations at the moment then complex numbers are quite a way off yet
Its her first secondary year, think they call it year 7 nowdays. I want to help as much as i can as i wasted too much of those years and do not want her to end up the same.
Ah that would be why I am so confused then
Soldato
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root(-1) is an imaginary number ie 'not real' because there is no method in conventional mathematics of squaring a number to produce a negative answer.
it's a nightmare to work with when they crop up [such as in determining the stability of a control system]
it's a nightmare to work with when they crop up [such as in determining the stability of a control system]
Soldato
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Thank you for editing the topic title.
i
is a good answer
i
is a good answer
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But they are also incredibly useful, especially in Physics (pretty much every field of Physics too).
In-fact, if there is a solution to a problem which can be done using complex number then I generally pick that method as it often turns out to be more efficient (rather than needing to do 2 different trigonometric integrals you could just do a single complex exponential integral for example, that kind of thing crops up all the time).
Soldato
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true, the same can be said for matrices, doesnt mean i like doing maths with them
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true, the same can be said for matrices, doesnt mean i like doing maths with them
Well, matrices are just an absolute must in a lot of situations! That said, so are complex numbers too I guess.
Matrices aren't too bad though, linear algebra is fairly easy-going most of the time. Sure, I suppose if someone asks you to find the inverse of a 100x100 matrix on paper then you would have every right to tell them to go do one
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Well, matrices are just an absolute must in a lot of situations! That said, so are complex numbers too I guess.
Matrices aren't too bad though, linear algebra is fairly easy-going most of the time. Sure, I suppose if someone asks you to find the inverse of a 100x100 matrix on paper then you would have every right to tell them to go do one
In one of the question papers I've seen at uni, there was a 8x8 matrix and an inverse had to be calculated
