Higher Engineering Mathematics, Sixth Edition

(Nancy Kaufman) #1

230 Higher Engineering Mathematics



  1. Ifz=7ej^2.^1 , determine lnz(a) in Cartesian
    form, and (b) in polar form.⎡



(a)ln7+j 2. 1
(b) 2. 86 ∠ 47. 18 ◦or
2. 86 ∠ 0. 82




  1. Given z=4e^1.^5 −j^2 , determine lnzin polar
    form. [3. 51 ∠− 34. 72 ◦or 3. 51 ∠− 0 .61]

  2. Determine in polar form (a) ln( 2 +j 5 )
    (b) ln(− 4 −j 3 ) ⎡





(a) 2. 06 ∠ 35. 26 ◦or
2. 06 ∠ 0. 615
(b) 4. 11 ∠ 66. 96 ◦or
4. 11 ∠ 1. 17






  1. When displaced electrons oscillate about an
    equilibrium position the displacementx is
    given by the equation:


x=Ae

{
− 2 htm+j


( 4 mf−h^2 )
2 m−a t

}

Determine the real part ofx in terms oft,
assuming (4mf−h^2 ) is positive.
[
Ae−

ht
2 mcos

(√
( 4 mf−h^2 )
2 m−a

)
t

]
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