1.

lf `z = ilog(2-sqrt(-3))`, then `cos z =`A. `-1`B. `-1//2`C. 1D. 2

Answer» Correct Answer - D
`z=ilog(2=sqrt3)`
`rArr e^(iz)=e^(i"^(2)log(2-sqrt3))=e^(-log(2-sqrt3))`
`=e^(log(2-sqrt3)^(-1))=e^(log(2+sqrt3))=(2+sqrt3)`
`rArr cosz=(e^(iz)+e^(-iz))/(2)=((2+sqrt3)+(2-sqrt3))/(2)=2`


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