Math, asked by kakoburaman, 1 year ago

Find the values of x and y for which the following values are satisfied :
 \frac{(1 + i)x - 2i}{3 + i}  +  \frac{(2  -  3i)y  +  i}{3  -  i}   = i

Answers

Answered by sivaprasath
1

Answer:

x = 3,

y = -1

Step-by-step explanation:

Given :

To solve for x & y if,

\frac{(1+i)x - 2i}{3+i} + \frac{(2-3i)y+i}{3-i} = i

Solution :

\frac{(1+i)x - 2i}{3+i} + \frac{(2-3i)y+i}{3-i} = i

\frac{[(1+i)x - 2i](3-i)+[(2-3i)y+i](3+i)}{(3-i)(3+i)} = i

\frac{[3(1+i)x - i(1+i)x - 2i(-i) -2i(3)]+ [3(2 - 3i)y - i(2-3i)y +i(3-i)}{(3-i)(3+i)} = i

\frac{[3x + 3ix - ix - i^2x + 2i^2 -6i]+ [6y - 9iy + 2iy + 3i^2y +3i+i^2]}{9-i^2} = i

\frac{(4x + 9y - 3) +i(2x - 7y- 3)}{9-i^2} = i

(4x + 9y - 3) +i(2x - 7y- 3) = i(9+1)

(4x + 9y - 3) +i(2x - 7y- 3) = 10i

⇒  (4x + 9y - 3) = 0 and i(2x - 7y- 3) = 10i2x - 7y- 3) = 10

4x + 9y = 3  ...(i) and 2x - 7y = 13 ...(ii)

By adding both the equation (i) × 7 & (ii) × 9

 7 ( 4x + 9y ) + 9 (2x - 7y) = 7 × 3 + 9 × 13

 28x + 63y + 18x - 63y = 21 + 117

 46x = 138

x = 3

By substituting the value of x in (i),

We get,

 4x + 9y = 3

 4(3) + 9y = 3

⇒   12+ 9y = 3

⇒  9y = 3 - 12 = -9

y = -1


kakoburaman: yes you solved it correctly, I was getting same...
kakoburaman: but it seems too long Tbh, suspiciously long
kakoburaman: I really think there has to be some shortcut
sivaprasath: Ya,. The funny thing about this is, In my half-yearly exam I got the same question for 6 marks ,.
sivaprasath: I solved it correctly but I messed with the denominator as (3 - i)(3 + i) = 3 - i^2 = 4 & lost 5 marks,. I got 94.5 out of 100,. It was lengthy for me too.
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