guyz i need help wif complex numbers (1 Viewer)

[bleakarcher]

in vector representation of complex numbers, i dont understand the concept of adding/subtracting the vectors and when to add or subtract. can someone explain this to me? thanks in advanced

 

[OldMathsGuy]

What text are you using?
Also have you got a specific harder question in mind?
The key to these questions is having a good graphical picture of what's going on. When you subtract a vector, you are adding its additive inverse. For example if you wish to add 3 - i to z, then that is exactly what you do (like a boat navigating to the point z and then navigating a further 3 - i to the new position z + 3 - i). [where z = a + ib]
To subtract 3 - i, you instead add the additive inverse -3 + i to z (which is like the boat navigating to z then going the same distance as before but in the opposite direction to the new position z - 3 + i).

Does that help at all?

Best Regards
OldMathsGuy

 

[bleakarcher]

lol thanks oldmathsguy, that would have helped if i hadnt found this one youtube tutorial on addition and subtraction of vectors. i understand it now, i guess having a teacher does help coz ive been teaching myself mxII content. anywayz yeh. now that i am able to do proof, there actually interesting although sometimes i cant find a way through lol. yeh ive noticed a good graph helps. i have approx. 2 yrz till my mxII hsc exam, i think ill have good time to get myself ready

 

[OldMathsGuy]

Props on directing yourself with the Ext 2 coursework by the way. It takes some dedication to do that.

Not wanting to pry too much but where are you at with your 2U and Ext1 work? If you are still finding your feet with this coursework and you really want to get ahead of the game, then the following may be helpful (otherwise please ignore):

In Ext 2, you can most likely cover some of complex numbers, and a bit of graphs, and some polynomials but then you are going to hit this almighty brick wall called Calculus. The foundations of calculus are built in the 2U course, extended in the 3U course and then further explored in the 4U course (which covers a fair chunk of the stuff in a traditional 1st year uni maths course). About a half and generally more of each of these maths papers is devoted to some application of calculus. I would suggest absolutely nailing the 2U material first before stressing too much about the Ext2 course as I think in terms of time/effort it is going to be more productive. For example at the moment, you might have to put in 4 hours of work to do what a Y12 student (with all the mathematical experiences that go with that) could do in an hour. What you are better off doing then is becoming that Y12 student at the start of Y11 (something that should not be that difficult with the obvious dedication you seem to have). The way to do that is to really nail all that foundational 2U Calculus (differentiation and integration). Then next year you can focus on Extension 1 and all the hell it can bring to the table, leaving Y12 for the mountain of work that is 4 unit maths (Extension 2 for the young ones). This is the most efficient way of traversing the coursework in the smallest amount of time and with the least effort. Such is what I suggest (and would be more than happy to direct you with; if you keep asking questions, I'd be more than happy to keep answering them).

If you are creaming 2U and Extension 1 maths and putting past papers easily to the sword, please ignore the above and enjoy your Extension 2 coursework.

Best Regards
OldMathsGuy

 

[bleakarcher]

lol. mx1 and 2 unit maths were no trouble really. although 3 unit circle geometry is sometimez difficult, most of the times it is fine and perms and combs are hard as well. the rest ive covered fine. mx2 ive done integration, volumes, most of graphs and now complex numbers

 

[OldMathsGuy]

lol. mx1 and 2 unit maths were no trouble really. although 3 unit circle geometry is sometimez difficult, most of the times it is fine and perms and combs are hard as well. the rest ive covered fine. mx2 ive done integration, volumes, most of graphs and now complex numbers

No problem then. In which case I suggest keep doing past papers of all stripes (2U, Ext 1, Ext 2 HSC and about 290 trial 4u papers on Derek Buchanan's website). Which textbook are you using for Extension 2 by the way?

Best Regards
OldMathsGuy

 

[bleakarcher]

cambridge