Author Topic: Complex numbers Question A2 maths  (Read 1395 times)

Offline loggerhead

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Complex numbers Question A2 maths
« on: October 23, 2009, 01:13:25 am »
please help me with this question

The complex number u is given by
u = 7 + 4i
      3 - 2i

(i) Express u in the form x + iy, where x and y are real.              [3]

(ii) Sketch an Argand diagram showing the point representing the complex number u. Show on the same diagram the locus of the complex number z such that |z - u|= 2.            [3]

(iii) Find the greatest value of arg z for points on this locus.

i can do (i) and (ii) no problem but i need help with part 3 please

this is question 7 from CIE Maths paper 3 Oct/Nov 2003 which is attached

Offline sameer210394

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Re: Complex numbers Question A2 maths
« Reply #1 on: October 23, 2009, 06:33:47 am »
please help me with this question

The complex number u is given by
u = 7 + 4i
      3 - 2i

(i) Express u in the form x + iy, where x and y are real.              [3]

(ii) Sketch an Argand diagram showing the point representing the complex number u. Show on the same diagram the locus of the complex number z such that |z - u|= 2.            [3]

(iii) Find the greatest value of arg z for points on this locus.

i can do (i) and (ii) no problem but i need help with part 3 please

this is question 7 from CIE Maths paper 3 Oct/Nov 2003 which is attached

i'm gettin the answer for (iii) as 2.2 radians... just check,,, i donno if its right...
Son, if you really want something in this life, you have to work for it. Now quiet! They're about to announce the lottery numbers

Offline astarmathsandphysics

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Re: Complex numbers Question A2 maths
« Reply #2 on: October 23, 2009, 08:08:04 am »
Arg u + arcsin (2/|u|)
« Last Edit: October 23, 2009, 08:36:43 am by astarmathsandphysics »

Offline loggerhead

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Re: Complex numbers Question A2 maths
« Reply #3 on: October 24, 2009, 09:04:18 pm »
o yea, so simple.

thank you