# Laplace transform using differential equations

• I
Hi members,

Laplace transform using differential equations.(see attached PDF file)

My question d/ds(s^2 y- s Y(0)-Y'(0).).......
Y(t)=sin(sqrt(t)) Y(o)=0
Now Y'= cos(sqrt(t)/2sqrt(t) Y'(0)=infinity

d/ds (Y'(0)=?? can it be treated as a constant or can we change limit and differentiation??I don't think so.
like d/ds (cos(sqrt(t))/2sqrt(t)=0

Thank you

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• 20-06-2016 14;21;15.PDF
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Mark44
Mentor
Hi members,

Laplace transform using differential equations.(see attached PDF file)

My question d/ds(s^2 y- s Y(0)-Y'(0).).......
Y(t)=sin(sqrt(t)) Y(o)=0
Now Y'= cos(sqrt(t)/2sqrt(t) Y'(0)=infinity

d/ds (Y'(0)=??
Y(0) and Y'(0) are constants, so their derivatives are both zero.
Belgium 12 said:
can it be treated as a constant or can we change limit and differentiation??I don't think so.
like d/ds (cos(sqrt(t))/2sqrt(t)=0

Thank you

Hello Mark 44,

If I understand it,Y'(0)=infinity.Here infinity can be treated as a constant.

Thank you