मराठी

If the real part of z¯+2z¯-1 is 4, then show that the locus of the point representing z in the complex plane is a circle.

Advertisements
Advertisements

प्रश्न

If the real part of `(barz + 2)/(barz - 1)` is 4, then show that the locus of the point representing z in the complex plane is a circle.

बेरीज
Advertisements

उत्तर

Let z = x + iy

∴ `barz` = x – iy

So`(barz + 2)/(barz - 1) = (x - iy + 2)/(x - iy - 1)`

= `((x + 2) - iy)/((x - 1) - iy)`

= `((x + 2) - iy)/((x - 1) - iy) xx ((x - 1) + iy)/((x - 1) + iy)`

= `((x + 2)(x - 1) + (x + 2)yi - (x - 1)yi - i^2y^2)/((x - 1)^2 - i^2y^2)`

= `(x^2 + 2x - x - 2 + (x + 2 - x + 1)yi + y^2)/((x - 1)^2 + y^2)`

= `(x^2 + y^2 + x - 2)/((x - 1)^2 + y^2) + (3y)/((x - 1)^2 + y^2)i`

Real part = 4

∴ `(x^2 + y^2 + x - 2)/((x - 1)^2 + y^2)` = 4

⇒ x2 + y2 + x – 2 = 4[(x – 1)2 + y2]

⇒ x2 + y2 + x – 2 = 4[x2 + 1 – 2x + y2]

⇒ x2 + y2 + x – 2 = 4x2 + 4 – 8x + 4y2

⇒ x2 – 4x2 + y2 – 4y2 + x + 8x – 2 – 4 = 0

⇒ – 3x2 – 3y2 + 9x – 6 = 0

⇒ x2 + y2 – 3x + 2 = 0

Which represents a circle.

Hence, z lies on a circle.

shaalaa.com
  या प्रश्नात किंवा उत्तरात काही त्रुटी आहे का?
पाठ 5: Complex Numbers and Quadratic Equations - Exercise [पृष्ठ ९१]

APPEARS IN

एनसीईआरटी एक्झांप्लर Mathematics [English] Class 11
पाठ 5 Complex Numbers and Quadratic Equations
Exercise | Q 9 | पृष्ठ ९१

व्हिडिओ ट्यूटोरियलVIEW ALL [1]

संबंधित प्रश्‍न

Find the multiplicative inverse of the complex number.

–i 


Find the number of non-zero integral solutions of the equation `|1-i|^x  = 2^x`.


Simplify the following and express in the form a + ib: 

(2i3)2 


Simplify the following and express in the form a + ib:

`(4 + 3"i")/(1 - "i")`


Find the value of : x3 + 2x2 – 3x + 21, if x = 1 + 2i


Write the conjugates of the following complex number:

3 – i


Write the conjugates of the following complex number:

`-sqrt(5) - sqrt(7)"i"`


Find the value of 1 + i2 + i4 + i6 + i8 + ... + i20


Find the value of `("i"^6 + "i"^7 + "i"^8 + "i"^9)/("i"^2 + "i"^3)`


If (a + ib) = `(1 + "i")/(1 - "i")`, then prove that (a2 + b2) = 1


If (x + iy)3 = y + vi then show that `(y/x + "v"/y)` = 4(x2 – y2)


Answer the following:

Simplify the following and express in the form a + ib:

(2 + 3i)(1 − 4i)


Answer the following:

Simplify the following and express in the form a + ib:

`5/2"i"(-4 - 3"i")`


Answer the following:

Simplify the following and express in the form a + ib:

`(5 + 7"i")/(4 + 3"i") + (5 + 7"i")/(4 - 3"i")`


Answer the following:

Find the value of x4 + 9x3 + 35x2 − x + 164, if x = −5 + 4i


Answer the following:

Show that `(1 - 2"i")/(3 - 4"i") + (1 + 2"i")/(3 + 4"i")` is real


If |z1| = 1, |z2| = 2, |z3| = 3 and |9z1z2 + 4z1z3 + z2z3| = 12, then the value of |z1 + z2 + z3| is


Find the value of k if for the complex numbers z1 and z2, `|1 - barz_1z_2|^2 - |z_1 - z_2|^2 = k(1 - |z_1|^2)(1 - |"z"_2|^2)`


The value of `(- sqrt(-1))^(4"n" - 3)`, where n ∈ N, is ______.


State true or false for the following:

Multiplication of a non-zero complex number by i rotates it through a right angle in the anti-clockwise direction.


State true or false for the following:

If three complex numbers z1, z2 and z3 are in A.P., then they lie on a circle in the complex plane.


What is the value of `(i^(4n + 1) -i^(4n - 1))/2`?


Evaluate `sum_(n = 1)^13 (i^n + i^(n + 1))`, where n ∈ N.


If `(1 + i)^2/(2 - i)` = x + iy, then find the value of x + y.


If `(z - 1)/(z + 1)` is purely imaginary number (z ≠ – 1), then find the value of |z|.


If |z1| = 1(z1 ≠ –1) and z2 = `(z_1 - 1)/(z_1 + 1)`, then show that the real part of z2 is zero.


If |z1| = |z2| = ... = |zn| = 1, then show that |z1 + z2 + z3 + ... + zn| = `|1/z_1 + 1/z_2 + 1/z_3 + ... + 1/z_n|`.


Find the complex number satisfying the equation `z + sqrt(2) |(z + 1)| + i` = 0.


The number `(1 - i)^3/(1 - i^2)` is equal to ______.


If z1 and z2 are complex numbers such that z1 + z2 is a real number, then z2 = ______.


Find `|(1 + i) ((2 + i))/((3 + i))|`.


The point represented by the complex number 2 – i is rotated about origin through an angle `pi/2` in the clockwise direction, the new position of point is ______.


The complex number z which satisfies the condition `|(i + z)/(i - z)|` = 1 lies on ______.


If z is a complex number, then ______.


Find the value of `(i^592+i^590+i^588+i^586+i^584)/(i^582+i^580+i^578+i^576+i^574)`


Simplify the following and express in the form a+ib.

`(3"i"^5 + 2"i"^7 + "i"^9)/("i"^6 + 2"i"^8 + 3"i"^18)`


Evaluate the following:

i35


If z = 2 + i, then (z − 1) `(barz − 5) + (barz − 1)` (z − 5) is equal to ______.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×