Hello,

May i know how to integrate this 2 x integrate exp(-2t)dt?
Why is the answer is 1? Please advise. Thanks.

 

2*Int(exp(-2t))dt = -1/(2*exp(t)^2 + C

an integral can only equal one IF it is perfomed with integration limits. THe result of an integration is always a function of the integration operand

 

wouldnt it be -exp(-2t) + C? the term inside the exp doesnt change.
(I plugged it into my calculator, and thats what it gave me)

__________________
Jeff
To the optimist, the glass is half full.
To the pessimist, the glass is half empty.
To the engineer, the glass is twice as big as it needs to be.

 

oh yer did a mistake on that 1

 

integrate exp(-2t) = -1/2(exp(-2t))
and since 2 in Nr, and Dr divide out the final outcome is
- (exp(-2t))
May be if you want the ans to be 1 you can write
-(exp(-2t)) = 1 and find the value for t hence getting the limits of integration. i suppose t = - infinity, OR simply 1 cannot be the answer
Here initial value again is not taken into account
I guess i repeated all the above suggestions

 

Hi all,

The Q is something like this.

Determine the energy and power of the signal y(t) = exp (-t).
Check if this function is a energy or power type.
Please advise. Thanks.

 

e^0 = 1

so at t = 0, the function will equal 1.

 

except that it is an integration and MUST be over a time range.

that function should equal 0 at t=Inf so an integration boundary of t=0 to t=inf will give you a value of 1