Integral involving Heaviside function in the exponential











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I need to compute the following integral in the real domain that involves the Heaviside step function $Theta(x)$:



$$
int_0^{infty} e^{- alpha_0Theta(x)- alpha_1 x} dx
$$



with $alpha_0, alpha_1$ two real constants.
Is there some useful representation of the Heaviside $Theta$ function that I can exploit to calculate the integral?



Or should I compute the integral using some complex plane technique?










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  • 1




    Well, the step function is $+1$ on your entire domain of integration, so this is just $e^{-alpha_0} int_0^{infty} e^{-alpha_1 x} , dx$....
    – T. Bongers
    Nov 28 at 14:55










  • Yes, use the definition of that function.
    – Yves Daoust
    Nov 28 at 14:57















up vote
0
down vote

favorite












I need to compute the following integral in the real domain that involves the Heaviside step function $Theta(x)$:



$$
int_0^{infty} e^{- alpha_0Theta(x)- alpha_1 x} dx
$$



with $alpha_0, alpha_1$ two real constants.
Is there some useful representation of the Heaviside $Theta$ function that I can exploit to calculate the integral?



Or should I compute the integral using some complex plane technique?










share|cite|improve this question


















  • 1




    Well, the step function is $+1$ on your entire domain of integration, so this is just $e^{-alpha_0} int_0^{infty} e^{-alpha_1 x} , dx$....
    – T. Bongers
    Nov 28 at 14:55










  • Yes, use the definition of that function.
    – Yves Daoust
    Nov 28 at 14:57













up vote
0
down vote

favorite









up vote
0
down vote

favorite











I need to compute the following integral in the real domain that involves the Heaviside step function $Theta(x)$:



$$
int_0^{infty} e^{- alpha_0Theta(x)- alpha_1 x} dx
$$



with $alpha_0, alpha_1$ two real constants.
Is there some useful representation of the Heaviside $Theta$ function that I can exploit to calculate the integral?



Or should I compute the integral using some complex plane technique?










share|cite|improve this question













I need to compute the following integral in the real domain that involves the Heaviside step function $Theta(x)$:



$$
int_0^{infty} e^{- alpha_0Theta(x)- alpha_1 x} dx
$$



with $alpha_0, alpha_1$ two real constants.
Is there some useful representation of the Heaviside $Theta$ function that I can exploit to calculate the integral?



Or should I compute the integral using some complex plane technique?







calculus integration






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share|cite|improve this question











share|cite|improve this question




share|cite|improve this question










asked Nov 28 at 14:54









linello

17011




17011








  • 1




    Well, the step function is $+1$ on your entire domain of integration, so this is just $e^{-alpha_0} int_0^{infty} e^{-alpha_1 x} , dx$....
    – T. Bongers
    Nov 28 at 14:55










  • Yes, use the definition of that function.
    – Yves Daoust
    Nov 28 at 14:57














  • 1




    Well, the step function is $+1$ on your entire domain of integration, so this is just $e^{-alpha_0} int_0^{infty} e^{-alpha_1 x} , dx$....
    – T. Bongers
    Nov 28 at 14:55










  • Yes, use the definition of that function.
    – Yves Daoust
    Nov 28 at 14:57








1




1




Well, the step function is $+1$ on your entire domain of integration, so this is just $e^{-alpha_0} int_0^{infty} e^{-alpha_1 x} , dx$....
– T. Bongers
Nov 28 at 14:55




Well, the step function is $+1$ on your entire domain of integration, so this is just $e^{-alpha_0} int_0^{infty} e^{-alpha_1 x} , dx$....
– T. Bongers
Nov 28 at 14:55












Yes, use the definition of that function.
– Yves Daoust
Nov 28 at 14:57




Yes, use the definition of that function.
– Yves Daoust
Nov 28 at 14:57















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