If z1 = (2 – i) and z2 = (1 + i), find .

Given: z1 = (2 – i) and z2 = (1 + i)

To find:


Consider,



Putting the value of z1 and z2, we get





Now, rationalizing by multiply and divide by the conjugate of 1 – i




[(a – b)(a + b) = a2 – b2]



[Putting i2 = -1]



= |2(1 + i)|


= |2 + 2i|


Now, we have to find the modulus of (2 + 2i)


So,



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