NCERT Class XI Mathematics - Complex Numbers and Quadratic Equations - Solutions
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Question : 21
Total: 52
Solution:
We have , √ 3 + i
Let√ 3 = r cosθ …(i) and 1 = r sinθ …(ii)
Squaring and adding (i) and (ii), we get
r 2 ( c o s 2 θ + s i n 2 θ ) = 3 + 1 ⇒ r 2 = 4 ⇒ r = 2
Substituting the value of r in (i) and (ii), we get 2 cos θ =√ 3 , 2 sin θ = 1
⇒ cos θ =
, sin θ =
⇒ cos θ = cos
, isn θ = sin
Here , cos θ and sin θ both are positive.
∴ θ lies in first quadrant. ∴ θ =
∴ The required polar form is z = 2( c o s
+ i s i n
)
Let
Squaring and adding (i) and (ii), we get
Substituting the value of r in (i) and (ii), we get 2 cos θ =
⇒ cos θ =
Here , cos θ and sin θ both are positive.
∴ θ lies in first quadrant. ∴ θ =
∴ The required polar form is z = 2
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