05 सम्मिश्र संख्याएँ और द्विघात समीकरण

अभ्यास 01

Question:

Find the multiplicative inverse of the complex number −i

Answer:

Answer: Step 1: The multiplicative inverse of any number is the reciprocal of the number.

Step 2: The reciprocal of -i is 1/-i.

Step 3: Therefore, the multiplicative inverse of -i is 1/-i.

Question:

Express the given complex number in the form a+ib:(1−i)4

Answer:

(1-i)^4 = (1-i)(1-i)(1-i)(1-i) = (1-i)(1-i)(1-i-i) = (1-i)(1-2i) = (1-2i-i^2) = (1-2i-1) = 1-2i-1+i^2 = 1-2i-1+(-1) = 1-2i-2 = 1-2(i+1) = 1-2i-2i = 1-4i = a+ib = 1-4i

Therefore, the complex number in the form a+ib is 1-4i.

Question:

Find the multiplicative inverse of the complex number √5+3i.

Answer:

Answer: Step 1: Find the conjugate of the complex number √5+3i. Conjugate = √5-3i

Step 2: Find the modulus of the complex number √5+3i. Modulus = |√5+3i| = √(5^2 + 3^2) = √34

Step 3: Find the multiplicative inverse of the complex number √5+3i. Multiplicative inverse = (√5-3i)/√34

Question:

(5i)(−3​/5i)

Answer:

  1. First, combine the two terms by adding them: 5i + (-3/5i)

  2. Simplify the terms by multiplying the numerator and denominator of the second term by the complex conjugate of the denominator of the second term: 5i + (-3/(5i)(-5i)) = 5i + (15/25)

  3. Simplify the terms by combining the coefficients of the terms: 5i + 15/25 = (5i + 15)/25

  4. Simplify the terms by multiplying the numerator and denominator by the reciprocal of the denominator: (5i + 15)/25 * 25/25 = (5i + 15)/25 * 1 = (5i + 15)

Question:

Solve : i9+i19

Answer:

Step 1: Rewrite the expression using the power of a power rule.

i^9 + i^19 = i^(9+19)

Step 2: Calculate the value of i^(9+19).

i^(9+19) = i^28

Question:

Express the given complex number 3(7+i7)+i(7+i7) in the form a+ib,

Answer:

Given: 3(7+i7)+i(7+i7)

Step 1: 3(7+i7) = 21 + 3i7

Step 2: i(7+i7) = -7 + i7

Step 3: 21 + 3i7 + (-7 + i7)

Step 4: 21 - 7 + 4i7

Answer: 21 - 7 + 4i7 = 14 + 4i7

Question:

Express the given complex number in the form a+ib: (−2−1​/3i)3

Answer:

Given complex number, z = (-2 - i/3)

Step 1: Calculate z^3

z^3 = (-2 - i/3)^3

Step 2: Expand the expression

(-2 - i/3)^3 = -8 - 8i/3 - 2i^2/3 - (i/3)^3

Step 3: Simplify the expression

-8 - 8i/3 - 2i^2/3 - (i/3)^3 = -8 - 8i/3 - 2i^2/3 - i/27

Step 4: Express in the form a+ib

-8 - 8i/3 - 2i^2/3 - i/27 = -8 - 8i/3 - 2i^2/3 - i/27 = -8 - 8i/3 - 2i - i/9 = -8 - 10i - i/9

Therefore, the given complex number in the form a+ib is: -8 - 10i - i/9

Question:

Express the following expression in the form of a+ib ; (3+i√5)(3−i√5)/(√3+√2i)−(√3−i√2)

Answer:

Given, (3+i√5)(3−i√5)/(√3+√2i)−(√3−i√2)

Step 1: Multiply the numerator and denominator by the conjugate of the denominator.

(3+i√5)(3−i√5)(√3-√2i)/((√3+√2i)(√3-√2i))-((√3−i√2)(√3-√2i))

Step 2: Simplify the numerator and denominator.

(3+i√5)(3−i√5)(3+√2i)/(9+2i√6)-(3+√2i)(3+√2i)

Step 3: Simplify the numerator and denominator further.

(9-5√5)/(9+2i√6)-9

Step 4: Simplify the expression further.

-14-2i√6/9+2i√6

Step 5: Express the expression in the form of a+ib.

-14/9+2i√6/9

Question:

Solve: [(1​/3+i7​/3)+(4+i1​/3)]−(−4​/3+i)

Answer:

Step 1: Combine like terms on the left side of the equation: [(1​/3+i7​/3)+(4+i1​/3)]−(−4​/3+i)

Step 2: [(5​/3+i8​/3)]−(−4​/3+i)

Step 3: [5​/3+i8​/3 + 4​/3-i]

Step 4: 9​/3+i7​/3

Question:

Express (31​+3i)3 in the form a+ib. A 343​/34+23i B −343​/34−23i C 242​/27+26i D −242​/27−26i

Answer:

Answer: C 242​/27+26i

Question:

Find the modulus and amplitude of 4+3i.

Answer:

Answer: Modulus: 5 Amplitude: 5

Question:

Express (1−i)−(1+i6) as a+ib

Answer:

(1−i)−(1+i6) = (1−i) − 1 - i6 = -i - 1 - i6 = -i - 1 - (i/6) = -i - 1 - (1/6)i = -i - 1 + (-1/6)i = -i - 1 + (1/6)i = (-1 - 1 + (1/6))i = (-2 + (1/6))i = (-2 + (1/6))(1 + i) = (-2 + (1/6)) + (-2 + (1/6))i = (-2 + (1/6)) + i(-2 + (1/6)) = a + ib = (-2 + (1/6)) + i(-2 + (1/6)) = (-2 + (1/6)) + i(-2 + (1/6))

Question:

Solve the problem:- (1​/5+i2​/5)−(4+i5​/2)

Answer:

Given, (1/5 + i2/5) - (4+i5/2)

Step 1: Rewrite the given expression as,

(1/5 + i2/5) - (4+ i5/2) = (1/5 - 4) + (i2/5 - i5/2)

Step 2: Simplify the expression,

(1/5 - 4) + (i2/5 - i5/2) = -3.8 + (-3.5i)

Hence, the solution is -3.8 + (-3.5i).

Question:

Evaluate i−39.

Answer:

i^−39 = 1/i^39

= 1/(i^2)^19

= 1/i^38

= 1/i^2 * 1/i^36

= 1/i^2 * (1/i^18)^2

= 1/i^2 * (1/i^2)^18

= (1/i^2)^19

जेईई अध्ययन सामग्री (गणित)

01 सेट

02 संबंध एवं फलन

03 त्रिकोणमितीय फलन

04 गणितीय आगमन का सिद्धांत

05 सम्मिश्र संख्याएँ और द्विघात समीकरण

06 रैखिक असमानताएँ

07 क्रमचय और संचय

08 द्विपद प्रमेय

09 अनुक्रम और श्रृंखला

10 सीधी रेखाओं का अभ्यास

10 सीधी रेखाएँ विविध

11 शांकव खंड

12 त्रिविमीय ज्यामिति का परिचय

13 सीमाएं और डेरिवेटिव

14 गणितीय तर्क

15 सांख्यिकी

16 प्रायिकता