English

Show that ii(12+i2)10+(12-i2)10 = 0

Advertisements
Advertisements

Question

Show that `(1/sqrt(2) + "i"/sqrt(2))^10 + (1/sqrt(2) - "i"/sqrt(2))^10` = 0

Sum
Advertisements

Solution

`(1/sqrt(2) + "i"/sqrt(2))^2 = 1/2 + 2(1/sqrt(2)) ("i"/sqrt(2)) + "i"^2/2`

= `1/2 + "i" - 1/2` = i

∴ `(1/sqrt(2) + "i"/sqrt(2))^10 = [(1/sqrt(2) + "i"/sqrt(2))^2]^5 = i^5 = i^4 * i = 1*i = i     ...(i)`

Also, `(1/sqrt(2) - "i"/sqrt(2))^2 = 1/2 - 2(1/sqrt(2)) ("i"/sqrt(2)) + "i"^2/2`

= `1/2 - "i" - 1/2` = – i

∴ `(1/sqrt(2) - "i"/sqrt(2))^10 = [(1/sqrt(2) - "i"/sqrt(2))^2]^5 =(-i)^5 = i^4 * (-i) = 1*(-i) = -i      ...(ii)`

Adding (i) and (ii), we get

`(1/sqrt(2) + "i"/sqrt(2))^10 + (1/sqrt(2) - "i"/sqrt(2))^10` = i – i = 0

Hence proved.

shaalaa.com
  Is there an error in this question or solution?
Chapter 1: Complex Numbers - Miscellaneous Exercise 1.2 [Page 22]

APPEARS IN

RELATED QUESTIONS

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 


Find the value of i + i2 + i3 + i4 


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

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


Write the conjugates of the following complex number:

`sqrt(5) - "i"`


Simplify:

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


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


If x + iy = (a + ib)3, show that `x/"a" + y/"b"` = 4(a2 − b2)


If x + iy = `sqrt(("a" + "ib")/("c" + "id")`, prove that (x2 + y2)2 = `("a"^2 + "b"^2)/("c"^2 + "d"^2)` 


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


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

(x + 2y) + (2x − 3y)i + 4i = 5


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:

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


Answer the following:

Simplify: `("i"^29 + "i"^39 + "i"^49)/("i"^30 + "i"^40 + "i"^50)`


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


The argument of the complex number `(4 + 9i)/(13 + 5i)` is ______


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


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


The value of `(- sqrt(-1))^(4"n" - 3)`, where n ∈ N, 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 points representing the complex number z for which |z + 1| < |z − 1| lies in the interior of a circle.


State true or false for the following:

If n is a positive integer, then the value of in + (i)n+1 + (i)n+2 + (i)n+3 is 0.


What is the principal value of amplitude of 1 – i?


The area of the triangle on the complex plane formed by the complex numbers z, –iz and z + iz is ______.


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.


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


State True or False for the following:

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


Where does z lie, if `|(z - 5i)/(z + 5i)|` = 1.


The value of `(z + 3)(barz + 3)` is equivalent to ______.


If a + ib = c + id, then ______.


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 ______.


If α and β are the roots of the equation x2 + 2x + 4 = 0, then `1/α^3 + 1/β^3` is equal to ______.


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.

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


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


i2 + i3 + ... + i4000 =


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×