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HomeCBSE Class 11mathematicsComplex Numbers — Algebra, Powers of i, Modulus, Conjugate, Multiplicative Inverse, Argand Plane › Express (5 + √2 i)/(1 - √2 i) in the form a + ib.

Express (5 + √2 i)/(1 - √2 i) in the form a + ib.

A-3 + 2√2 i
B1 + 2√2 i
C1 - 2√2 i
D5 - √2 i
Answer & Solution
Correct answer: B. 1 + 2√2 i
Multiply by conjugate (1 + √2 i)/(1 + √2 i): numerator = (5 + √2 i)(1 + √2 i) = 5 + 5√2 i + √2 i - 2 = 3 + 6√2 i. Denominator = 1 - (√2 i)² = 1 + 2 = 3. Result = (3 + 6√2 i)/3 = 1 + 2√2 i.
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