English

If a = -1+3i2, b = -1-3i2 then show that a2 = b and b2 = a

Advertisements
Advertisements

Question

If a = `(-1 + sqrt(3)"i")/2`, b = `(-1 - sqrt(3)"i")/2` then show that a2 = b and b2 = a

Sum
Advertisements

Solution

a = `(-1 + sqrt(3)"i")/2`, b = `(-1 - sqrt(3)"i")/2`

∴ a2 = `((-1 + sqrt(3)"i")/2)^2 = (1 - 2sqrt(3)"i" + 3"i"^2)/4`

= `(1 - 2sqrt(3)"i" + 3(-1))/4`   ...[∵ i2 = – 1]

= `(-2 - 2sqrt(3)"i")/4`

= `(-1 - sqrt(3)"i")/2` = b

and b2 = `((-1 - sqrt(3)"i")/2)^2 = (1 + 2sqrt(3)"i" + 3"i"^2)/4`

= `(1 + 2sqrt(3)"i" + 3(-1))/4`   . ...[∵ i2 = – 1]

= `(-2 + 2sqrt(3)"i")/4`

= `(-1 + sqrt(3)"i")/2` = a

shaalaa.com
  Is there an error in this question or solution?
Chapter 1: Complex Numbers - Exercise 1.1 [Page 6]

RELATED QUESTIONS

If `x – iy = sqrt((a-ib)/(c - id))` prove that `(x^2 + y^2) = (a^2 + b^2)/(c^2 + d^2)`


Show that 1 + i10 + i20 + i30 is a real number.


Find the value of: x3 –  x2 + x + 46, if x = 2 + 3i


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

`3 + sqrt(-64)`


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

(2i3)2 


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

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


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

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


Find the value of i49 + i68 + i89 + i110 


Show that 1 + i10 + i100 − i1000 = 0 


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


If `("a" + 3"i")/(2+ "ib")` = 1 − i, show that (5a − 7b) = 0


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

`((x + "i"y))/(2 + 3"i") + (2 + "i")/(2 - 3"i") = 9/13(1 + "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


Answer the following:

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

`(1 + 2/"i")(3 + 4/"i")(5 + "i")^-1`


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 x3 + 2x2 − 3x + 21, if x = 1 + 2i


Answer the following:

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


If z1 = 5 + 3i and z2 = 2 - 4i, then z1 + z2 = ______.


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|.


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


State true or false for the following:

The points representing the complex number z for which |z + 1| < |z − 1| lies in the interior of a circle.


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


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.


If |z + 1| = z + 2(1 + i), then find z.


State True or False for the following:

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


State True or False for the following:

For any complex number z the minimum value of |z| + |z – 1| is 1.


State True or False for the following:

The inequality |z – 4| < |z – 2| represents the region given by x > 3.


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 ______.


Let x, y ∈ R, then x + iy is a non-real complex number if ______.


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


If `(3 + i)(z + barz) - (2 + i)(z - barz) + 14i` = 0, then `barzz` is equal to ______.


If a complex number z satisfies the equation `z + sqrt(2)|z + 1| + i` = 0, then |z| is equal to ______.


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.

`(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`


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

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


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×