हिंदी

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

Advertisements
Advertisements

प्रश्न

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

योग
Advertisements

उत्तर

Let z1 = x + yi

|z1| = `sqrt(x^2 + y^2)` = 1   ......[Given that |z1| = 1]

⇒ x2 + y2 = 1  ......(i)

Now z2 = `(z_1 - 1)/(z_1 + 1)`

= `(x + yi - 1)/(x + yi + 1)`

= `((x + 1) + y"i")/((x + 1) + y"i")`

= `((x - 1) + yi)/((x + 1) + yi) xx (x + 1 - yi)/(x + 1 - yi)`

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

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

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

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

= `0 + (2y)/(x^2 + y^2 + 2x + 1) "i"`

Hence, the real part of z2 is 0.

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 Exemplar [English] Class 11
अध्याय 5 Complex Numbers and Quadratic Equations
Exercise | Q 17 | पृष्ठ ९२

वीडियो ट्यूटोरियलVIEW ALL [1]

संबंधित प्रश्न

Find the multiplicative inverse of the complex number:

4 – 3i


If α and β are different complex numbers with |β| = 1, then find `|(beta - alpha)/(1-baralphabeta)|`


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


Find the value of i49 + i68 + i89 + i110 


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

`3 + sqrt(-64)`


Find the value of: x3 – 5x2 + 4x + 8, if x = `10/(3 - "i")`.


Find the value of: x3 – 3x2 + 19x – 20, if x = 1 – 4i


Write the conjugates of the following complex number:

cosθ + i sinθ


Simplify:

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


Show that 1 + i10 + i100 − i1000 = 0 


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


Find the value of x and y which satisfy the following equation (x, y∈R).

`(x+ 1)/(1 + "i") + (y - 1)/(1 - "i")` = i


Find the value of x and y which satisfy the following equation (x, y∈R).

If x + 2i + 15i6y = 7x + i3 (y + 4), find x + y


Select the correct answer from the given alternatives:

If n is an odd positive integer then the value of 1 + (i)2n + (i)4n + (i)6n is :


Answer the following:

Solve the following equation for x, y ∈ R:

`(x + "i"y)/(2 + 3"i")` = 7 – i


Answer the following:

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


Answer the following:

Simplify: `("i"^65 + 1/"i"^145)`


Answer the following:

Simplify: `("i"^238 + "i"^236 + "i"^234 + "i"^232 + "i"^230)/("i"^228 + "i"^226 + "i"^224 + "i"^222 + "i"^220)`


If z ≠ 1 and `"z"^2/("z - 1")` is real, then the point represented by the complex number z lies ______.


Evaluate: (1 + i)6 + (1 – i)3 


If z1, z2, z3 are complex numbers such that `|z_1| = |z_2| = |z_3| = |1/z_1 + 1/z_2 + 1/z_3|` = 1, then find the value of |z1 + z2 + z3|.


Find the value of 2x4 + 5x3 + 7x2 – x + 41, when x = `-2 - sqrt(3)"i"`.


The real value of ‘a’ for which 3i3 – 2ai2 + (1 – a)i + 5 is real is ______.


If (2 + i) (2 + 2i) (2 + 3i) ... (2 + ni) = x + iy, then 5.8.13 ... (4 + n2) = ______.


State true or false for the following:

The complex number cosθ + isinθ can be zero for some θ.


If `((1 + i)/(1 - i))^3 - ((1 - i)/(1 + i))^3` = x + iy, then find (x, y).


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


Solve the equation |z| = z + 1 + 2i.


Multiplicative inverse of 1 + i is ______.


The real value of α for which the expression `(1 - i sin alpha)/(1 + 2i sin alpha)` is purely real is ______.


If the least and the largest real values of α, for which the equation z + α|z – 1| + 2i = 0 `("z" ∈ "C" and "i" = sqrt(-1))` has a solution, are p and q respectively; then 4(p2 + q2) is equal to ______.


If z1, z2, z3 are complex numbers such that |z1| = |z2| = |z3| = `|1/z_1 + 1/z_2 + 1/z_3|` = 1, then |z1 + z2 + z3| is ______.


A complex number z is moving on `arg((z - 1)/(z + 1)) = π/2`. If the probability that `arg((z^3 -1)/(z^3 + 1)) = π/2` is `m/n`, where m, n ∈ prime, then (m + n) is equal to ______.


`((1 + cosθ + isinθ)/(1 + cosθ - isinθ))^n` = ______.


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

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


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

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


Find the value of `sqrt(-3) xx sqrt(-6)`


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×