हिंदी

If z and w are two complex numbers such that |zw| = 1 and arg(z) – arg(w) = π2, then show that z¯w = –i. - Mathematics

Advertisements
Advertisements

प्रश्न

If z and w are two complex numbers such that |zw| = 1 and arg(z) – arg(w) = `pi/2`, then show that `barz`w = –i.

योग

उत्तर

Let z = r1 (cosθ1 + isinθ1) and w = r2 (cosθ2 + isinθ2)

zw = r1r2 [(cosθ1 + isinθ1)] [(cosθ2 + isinθ2)]

|zw| = r1r2 = 1

Now arg(z) – arg(w) = `pi/2`

θ1 – θ2 = `pi/2`

⇒ arg `(z/w) = pi/2`

`barzw` = r1 (cosθ1 – isinθ1) r2 (cosθ2 + isinθ2)

= r1 r2 [cosθ1 cosθ2 + icosθ1 sinθ2 – isinθ1 cosθ2 – i2 sinθ1 sinθ2]

= r1 r2 [(cosθ1 cosθ2 + sinθ1 sinθ2) + i(cosθ1 sinθ2 – sinθ1 cosθ2)]

= r1 r2 [cos(θ2 – θ1) + isin(θ2 – θ1)]

= `r_1r_2 [cos((-pi)/2) + i sin((-pi)/2)]`

= `r_1r_2 [cos  pi/2 - i sin  pi/2]`

= 1  .....[0 – i]

Here `barzw` = –i.

Hence proved.

shaalaa.com
  क्या इस प्रश्न या उत्तर में कोई त्रुटि है?
अध्याय 5: Complex Numbers and Quadratic Equations - Exercise [पृष्ठ ९२]

APPEARS IN

एनसीईआरटी एक्झांप्लर Mathematics [English] Class 11
अध्याय 5 Complex Numbers and Quadratic Equations
Exercise | Q 24 | पृष्ठ ९२

वीडियो ट्यूटोरियलVIEW ALL [1]

संबंधित प्रश्न

Find the modulus and the argument of the complex number  `z = – 1 – isqrt3`


Find the modulus and the argument of the complex number `z =- sqrt3 + i`


Convert the given complex number in polar form: 1 – i


Convert the given complex number in polar form: – 1 + i


Convert the given complex number in polar form: – 1 – i


Convert the given complex number in polar form: –3


Convert the given complex number in polar form `sqrt3 + i`


Convert the following in the polar form:

`(1+3i)/(1-2i)`


Let z1 and z2 be two complex numbers such that `barz_1 + ibarz_2` = 0 and arg(z1 z2) = π. Then find arg (z1).


If |z| = 2 and arg(z) = `pi/4`, then z = ______.


The locus of z satisfying arg(z) = `pi/3` is ______.


The amplitude of `sin  pi/5 + i(1 - cos  pi/5)` is ______.


Show that the complex number z, satisfying the condition arg`((z - 1)/(z + 1)) = pi/4` lies on a circle.


If arg(z – 1) = arg(z + 3i), then find x – 1 : y. where z = x + iy.


z1 and z2 are two complex numbers such that |z1| = |z2| and arg(z1) + arg(z2) = π, then show that z1 = `-barz_2`.


If for complex numbers z1 and z2, arg (z1) – arg (z2) = 0, then show that `|z_1 - z_2| = |z_1| - |z_2|`.


arg(z) + arg`barz  (barz ≠ 0)` is ______.


State True or False for the following:

Let z1 and z2 be two complex numbers such that |z1 + z2| = |z1| + |z2|, then arg(z1 – z2) = 0.


Find z if |z| = 4 and arg(z) = `(5pi)/6`.


Find principal argument of `(1 + i sqrt(3))^2`.


|z1 + z2| = |z1| + |z2| is possible if ______.


The value of arg (x) when x < 0 is ______.


If arg(z) < 0, then arg(–z) – arg(z) = ______.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×