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1.Express in the form of A+iB a) ((1+2i)/(1+i)) n for n = ±1, ±2, ±3, ±4……….. b) ln(1+itan α) 2.Find the sqrt of a) x+ sqrt (-x 4 -x 2 -1) 3.Find the integral solutions of the equations a) (1-i) n =2 n 4.If 1 ω, ω 2 are the three cube roots of the unity then, prove that a) (a+b ω+c ω 2 ) 3 +(a+b ω 2 +c ω) 3 = (2a-b-c)(2b-c-a)(2c-a-b)=27abc if a+b+c = 0 b) 1. (2- ω)(2- ω 2 )+ 2. (3- ω)(3- ω 2 ) +3 (4- ω)(4- ω 2 )+…………+(n-1)(n- ω)(n- ω 2 ) = {n 2 (n+1) 2 /4 } – n 5.If sin α +sin β + sin γ = cos α +cos β + cos γ = 0 then show that , Σcos 3α = 3 cos (α+β+γ) and Σsin 3α = 3 sin (α+β+γ) 6. prove that tan (i ln {(a-ib)/(a+ib)} = 2ab/a 2 -b 2 7. if iz 3 +z 2 -z + i = 0 then show that IzI = 1 8. If IzI = 1 then prove that arg(z 2 +conj z) = ½ arg (z) 9.If α, β are the roots of the equation x 2 -2x+4=0 prove that α n +β n = 2 n+1 cos ). 10. Construct an equation whose roots are nth power of roots of equation x 2 -2x cos θ +1 =0 11.If x=e iθ and 2 ) = nc-1` then prove that 1+c cos θ = (1+nx)(1+ ) 12. prove that I1-conj Z 1 Z 2 I 2 - IZ 1 – Z 2 I 2 = (1-IZ 1 I 2 )(1 – IZ 2 I 2 ) 13. If ABC is atriangle and triangles BCX , CAY , ABZ are drawn on BC , CA , AB , directly similar to one another . Provce that the centroid of XYZ and ABC coincides. 14. IF z = x+iy and w= , IwI = 1 , then find the locus of z. 15.If i i^i^i^……n = A+iB principle values only being considered then prove that a) tan πA = B/A b) A 2 +B 2 = e -π B 16. let Z 1 and Z 2 be the roots of the equation z 2 + pz+q = 0 , where the coefficient p and q may be complex number . Let A and B represents Z 1 and Z 2 respectively . If P 2 = 4q cos 2 α/2


1.Express in the form of  A+iB


a)    ((1+2i)/(1+i))n for n = ±1, ±2, ±3, ±4………..


b)    ln(1+itan α)


2.Find the sqrt of


a)   x+ sqrt (-x4-x2-1)


3.Find the integral solutions of the equations


a)  (1-i)n=2n


4.If 1 ω, ω2 are the three cube roots of the unity then, prove that


a)  (a+b ω+c ω2)3+(a+b ω2+c ω)3= (2a-b-c)(2b-c-a)(2c-a-b)=27abc if a+b+c = 0


b)  1. (2- ω)(2- ω2)+  2. (3- ω)(3- ω2)  +3 (4- ω)(4- ω2)+…………+(n-1)(n- ω)(n- ω2) =  {n2(n+1)2/4 } – n


5.If sin α +sin β + sin γ = cos α +cos β + cos γ = 0 then show that ,


Σcos 3α =  3 cos  (α+β+γ)   and  Σsin 3α = 3 sin (α+β+γ)


6. prove that tan (i ln {(a-ib)/(a+ib)} = 2ab/a2-b2


7. if iz3+z2-z + i = 0 then show that IzI =  1


8.  If IzI = 1 then prove that  arg(z2+conj z) =   ½ arg (z)


9.If α, β are the roots of the equation x2-2x+4=0 prove that  αnn = 2n+1 cos ).


10. Construct an equation whose roots are nth power of roots of equation x2-2x cos θ +1 =0


11.If x=e and 2) = nc-1` then prove that 1+c cos θ =  (1+nx)(1+)


12. prove that            I1-conj Z1Z2I2 -  IZ1 – Z2I2  =   (1-IZ1I2)(1 – IZ2I2)


13. If ABC  is atriangle and triangles BCX , CAY  , ABZ are drawn on BC , CA ,  AB , directly similar to one another . Provce that the centroid of XYZ  and ABC coincides.


14. IF z = x+iy and w=  ,  IwI = 1 , then find the locus of z.


15.If ii^i^i^……n = A+iB  principle values only being considered then prove that


a) tan πA  =  B/A


b)  A2+B2 =  eB 


16.let Z1 and  Z2 be the roots of the equation z2+ pz+q = 0 , where the coefficient p and q may be complex  number . Let A and B  represents Z1 and Z2 respectively . If

P2 = 4q cos2α/2


Grade:12

2 Answers

Harsh Patodia IIT Roorkee
askIITians Faculty 907 Points
9 years ago
HI student

((1+2i)/(1+i))n
Rationalize and then make it in euler form i.e rei\Theta
and then apply demoivre’s theorem to get the answer in a +ib

If you have any problem on this reply on this thread.

Please post 1 question at a time. Put other question separately on different post
Ravi
askIITians Faculty 69 Points
9 years ago
9 Complete the question. Cos(?)

10 Find the roots which will becos θ+i sinθ,cos θ-i sinθ

i.e. e, e-iθ

Their nth powers will beeinθ, e-inθ ...(I)

Form the new eqn by (x-a)(x-b)=0

where a,b represent the nth powers of roots(from eqn I)

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