If z = x + i y is a complex number, then the value of expression [sinh x.cosh (iy) + cosh x.sinh (iy)] will be:
If z = x + i y is a complex number, then the value of expression [sinh x.cosh (iy) + cosh x.sinh (iy)] will be: Correct Answer sinh z
Formula used:
If complex number z = x + iy then hyperbolic sine can be expressed as:
- sinh(z) = sinh(x+iy) = sinh(x).cos(y) + i cosh(x).sin(y)
- cosh (z) = cos (iz)
- sinh (z) = - i cos(iz)
- cos(z) = cosh (iz)
- sin (z) = - i sinh (iz)
- sinh (iz) = i sin (z)
- sin(iz) = i sinh (z)
Calculation:
Let Z = ----(1)
Form the above property, we can say that,
cosh (iy) = cos y and
sinh (iy) = i sinh y
Therefore, from equation (1)
Z = Additional Information
Some of the important identities involving the hyperbolic functions are:
- cosh(z)2 - sinh(z)2 = 1
- sinh(z1+ z2) = sinh(z1)cosh(z2) + cosh(z1)sinh(z2)
- cosh(z1+ z2) = cosh(z1)cosh (z2) + sinh(z1)sinh(z2)
- sinh(z + 2π = sinh(z)
- cosh(z + 2π) = cosh(z)
- cosh(-z) = cosh(z)
- sinh(-z) = - sinh(z)
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Feb 20, 2025
