मराठी
महाराष्ट्र राज्य शिक्षण मंडळएचएससी विज्ञान (सामान्य) इयत्ता ११ वी

If (x + iy)3 = y + vi then show that v(yx+vy) = 4(x2 – y2)

Advertisements
Advertisements

प्रश्न

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

बेरीज
Advertisements

उत्तर

(x + yi)3 = y + vi 

∴ x3 + 3x2yi + 3xy2i2 + y3i3 = y + vi

∴ x3 + 3x2yi + 3xy2 (–1) – y3i = y + vi  ...[∵ i2 = – 1, i3 = – i]

∴  x3 + 3x2yi - 3xy2 – iy3 = y + vi 

∴ (x3 – 3xy2) + (3x2y – y3)i = y + vi

Equating real and imaginary parts, we get

y = x3 – 3xy2 and v = 3x2y – y3

∴ `y/x` = x2 – 3y2 and `"v"/y` = 3x2 – y2

Consider,

L.H.S = `y/x + "v"/y`

= x2 – 3y2 + 3x2 – y2

= 4x2 – 4y2

= 4(x2 – y2)

= R.H.S.

Hence proved.

shaalaa.com
  या प्रश्नात किंवा उत्तरात काही त्रुटी आहे का?
पाठ 1: Complex Numbers - Exercise 1.1 [पृष्ठ ६]

संबंधित प्रश्‍न

Find the multiplicative inverse of the complex number:

4 – 3i


Reduce `(1/(1-4i) - 2/(1+i))((3-4i)/(5+i))` to the standard form.


If (a + ib) (c + id) (e + if) (g + ih) = A + iB, then show that (a2 + b2) (c2 + d2) (e2 + f2) (g2 + h2) = A2 + B2.


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


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

(1 + 3i)2 (3 + i)


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

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


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


Write the conjugates of the following complex number:

3 + i


Is (1 + i14 + i18 + i22) a real number? Justify your answer


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


Answer the following:

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

(2i3)2 


Answer the following:

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

`(sqrt(5) + sqrt(3)"i")/(sqrt(5) - sqrt(3)"i")`


Answer the following:

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)`


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:

Solve the following equation for x, y ∈ R:

(4 − 5i)x + (2 + 3i)y = 10 − 7i


Answer the following:

Solve the following equation for x, y ∈ R:

`(x + "i"y)/(2 + 3"i")` = 7 – i


Answer the following:

Evaluate: (1 − i + i2)−15 


Answer the following:

Simplify `[1/(1 - 2"i") + 3/(1 + "i")] [(3 + 4"i")/(2 - 4"i")]`


If z1 = 2 – 4i and z2 = 1 + 2i, then `bar"z"_1 + bar"z"_2` = ______.


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)`


What is the reciprocal of `3 + sqrt(7)i`.


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


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


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


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


The sum of the series i + i2 + i3 + ... upto 1000 terms is ______.


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


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


Which of the following is correct for any two complex numbers z1 and z2?


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 ______.


The smallest positive integer n for which `((1 + i)/(1 - i))^n` = –1 is ______.


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)`


i2 + i3 + ... + i4000 =


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×