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NCERT Solution Complex Number Ex 4.1





Question 1:
Express the given complex number in the form a + ib: (5i)(-3i/5)
Question 2:
Express the given complex number in the form a + ib:
i9 +i19
Question 3:
Express the given complex number in the form a + ib: i-39
Question 4:
Express the given complex number in the form a + ib: 3(7 + i7) + i(7 + i7)
Question 5:
Express the given complex number in the form a + ib: (1 – i) – (–1 + i6)
Question 6:
Express the given complex number in the form a + ib:
(1/5+2i/5)-(4+i5/2)
Question 7:
Express the given complex number in the form a + ib:

Question 8
Express the given complex number in the form a + ib: (1 – i)4
Question 9:
Express the given complex number in the form a + ib: (1/3+3i)3
Question 10
Express the given complex number in the form a + ib: (-2-1i/3)3
Question 11:
Find the multiplicative inverse of the complex number 4 – 3i.
Question 12:
Find the multiplicative inverse of the complex number
NCERT Solution Complex Number Class 11 Exercise 4.1
Question 13
Find the multiplicative inverse of the complex number –i
Question 14
Express the following expression in the form of a + ib.

Solution 1
(5i)(-3i/5)
Multiplying
=-(15/5)i2
Now we know that
i2=-1
so
=3
Solution 2
 i9 +i19
=i2X4 +1 +i4X4 +3
=(i2)4 I + (i4)4 i3
Now i2=-1 so i4=1  and i3=-i
=i+(-i)
=i-i=0
Solution 3


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Solution 4:
 3(7 + i7) + i(7 + i7)
=21+21i+7i+7i2
Now i2=-1
So
=21+28i-7
=14+28i
Solution  5:
(1 – i) – (–1 + i6)
=2-7i
Solution 6:
(1/5+2i/5)-(4+i5/2)
=[(1/5)-4] +i[(2/5) –(5/2)]
=(-19/5) +(-21/10)i
Solution 7:

Solution 8
(1 – i)4
Can be written as
=[(1-i)2]2
=(1+i2-2i)2
=(1-1-2i)2
=4i2=-4
Solution 9

Solution 10

Solution 11
Let z=4-3i
Conjugate is given by
  =4+3i
Modulus is given by
|z|=5
Multiple inverse of any complex number z  is given by

Solution 12
Let z= √5+3i
Conjugate is given by
  = √5-3i
Modulus is given by
|z|=5+9=14
Multiple inverse of any complex number z  is given by

Solution 13
Let z=-i
Conjugate is given by
  =i
Modulus is given by
|z|=1
Multiple inverse of any complex number z  is given by

Solution 14

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