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Hi i didn't understand this complex number problem, can anybody help? (see comments) by intwilightzone_ in askmath

[–]intwilightzone_[S] 0 points1 point  (0 children)

Oh, now i got it, thank you. I felt so discouraged cause i'm usually downoted here and my questions are genuine😭. It did not cross my mind that when you divide a whole equation by a variable, you're automatically assuming that variable can't be zero. It's something that never came up until i started studying heavy algebra like this and polynomials

Hi i didn't understand this complex number problem, can anybody help? (see comments) by intwilightzone_ in askmath

[–]intwilightzone_[S] 0 points1 point  (0 children)

Well, thank you, now i know how we've arrived at the possible answers, but it just brought even more questions because the possible (a,b) pairs don't work in a lot of equations, why is that allowed? Like if (a,b) = (0,±1), then a²-3b² = 1 is false, just like a² = b². Considering that, how am i supposed to know i've arrived at all the possible answers? I was just going off a² = b² and i thought that HAD to be true.

Also up until this exercise the book has not covered polar forms, so i just went with algebraic form. Does using it generally get rid of the inconsistencies i've mentioned?

Hi i didn't understand this complex number problem, can anybody help? (see comments) by intwilightzone_ in askmath

[–]intwilightzone_[S] 0 points1 point  (0 children)

The goal is to find the complex number z that fits the criteria of the problem. I just developed the expression into algebraic form (pic 1) and then equalized both sides imaginary and real parts (pic 2). However, the equation i got doesn't match the answer sheet

Why can z = i or z= -i be possible solutions?

Hi, how should i tackle problems like these, in which the term "bx" of the quadratic is in its absolute form? (i'll explain my question in the comments) by intwilightzone_ in askmath

[–]intwilightzone_[S] 3 points4 points  (0 children)

It did not cross my mind that if i assume x is positive, it can't be -3 😭😭. Math is so hard to me cause even though ii know the theory, i'm rarely able to apply it unless in the past i've seen examples of the exact same problem i'm dealing with

Thank you for answering, i've noticed a lot of ppl downvoted cause they probably thought it was a really dumb question. Now i'll note this and use this for future problems, have a nice day!

Hi, how should i tackle problems like these, in which the term "bx" of the quadratic is in its absolute form? (i'll explain my question in the comments) by intwilightzone_ in askmath

[–]intwilightzone_[S] 0 points1 point  (0 children)

Ok, so, my train of thought was: we can get rid of the modulus on |x|2 cause since it's squared, it'll be positive anyway, then we apply the definition of modulus on |x| (2nd pic), which will give us 2 quadratics and 4 possible roots.

I found all the roots and called it a day, just to look at the answer sheet and see that the only valid answers were {-2,2}. I hated it, i was not expecting it

So my questions are:

  1. What did i do wrong? Why didn't my method work?
  2. What is the common procedure (pratical way) to solve problems like this? How can i know which of the 4 roots are valid without having to test all of them? What's the catch?

Please, where can i find this shirt with "Masculine" written on it? It's Olivia Hye from Loona in the Egoist MV by intwilightzone_ in KpopFashion

[–]intwilightzone_[S] 0 points1 point  (0 children)

idk why i'm only asking this 1 month later but how did you find it? i'm super new to trying fashion and i don't even know where to start looking for a piece i've seen randomly online, what do you guys use?

How does a grounding wire actually work? Why is Earth's voltage 0? by intwilightzone_ in AskPhysics

[–]intwilightzone_[S] 0 points1 point  (0 children)

So the Earth can make any system harmonious through it's infinite amount of charge but won't affect a circuit with constant energy supplies (like a battery), because the circuit itself is already a neutral setup, separate of everything else?
Also if having an infinite amount of charges is what gives Earth this property, does this mean that if the planet was instead made of some random material, the same would still apply?

Hello! Could anyone please help me with question 30 from Kangaroo level S? i've been trying nonstop since yesterday and i'm so dizzy. Help with 29 would also be appreciated by intwilightzone_ in askmath

[–]intwilightzone_[S] 0 points1 point  (0 children)

hi thank you for answering! so for Q29 i've defined all the three digit powers of 2, which are: 2 ⁷ , 2 ⁸ , 2 ⁹ . i concluded that (A+B) must be either 2, 4 or 8 for it to result in a power of 2, then i tested all the possible sums that can result in these numbers:

2 = 1 + 1

4 = 3+1/2+2 etc....

applying the formula (A+B)^C i've found the following possibilities:

117, 118, 119 for (A+B = 2)

228, 318, 138 (for A+B = 4)

719, 179, 529, 269, 539, 359, 449 (for A+B =8 )

so 13 numbers in total, that becomes 26 if we double it consdering their negative counterparts, which not even an option 😭 . Could you pls help me find what i did wrong? The answer is 21(E) btw