# How can i apply vector of time in this function?

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Samantha Pham on 22 Sep 2020
Edited: Adam Danz on 22 Sep 2020
I have these codes below that calculate I and Is.
When i use Brightness(40,10,3), it gave me the desired result. This is the single time value
i want to use Brightness with vector like this: Brightness(40,0:0.01:10,3), how do i change the codes below to use this
Note: this is errors i received when i tried to use for vector time value --> Variable y has an incorrect value. Your function was unable to calculate the correct brightness for multiple times (0:0.01:10). Utilize Eq. 1 to calculate the brightness without factoring in the power surge. Utilize Eq. 2 to calculate the ADDITIONAL brightness caused by the power surge. However, some time values in the vector will be less than the surge time; therefore, they will not have the additional brightness added by the surge. Use logical statements to add the additional surge brightness only to values at times greater than the time of surge.
function I = Brightness(Power, Time, Surge)
I = 15*Power*( 1 - 1.4*exp(-Time).*sin( 1.43*Time + pi/4 )); %equation 1
Is = 10*Power*exp(-1)*sin(1.43/2); %equation 2
for i = 1:length(Time)
if Time(i) > Surge
I(i) = I(i) + Is;
end
end

Samantha Pham on 22 Sep 2020
omg, i just need to change the sign, it works! Thank you so much, i have been doing this hw for days...
Turlough Hughes on 22 Sep 2020
Happy to help :)
Adam Danz on 22 Sep 2020
No need for the for-loop. Use indexing.
I = 15*Power*( 1 - 1.4*exp(-Time).*sin( 1.43*Time + pi/4 )); %equation 1
Is = 10*Power*exp(-1)*sin(1.43/2); %equation 2
idx = Time < Surge;
I(idx) = I(idx) + Is;