, what should i do
First of all, take a deep breath and try not to panic. You still have 4 hours left and that is enough time to prepare for your examination.
To solve the given question, you can use the substitution method. Let u = -a·x, then du = -a·dx and when x = 0, u = 0 and when x = +inf, u = -inf. So the integral becomes:
INT(ê^u·SIN(-u/a)/(-a), u, 0, -inf)
Using the substitution INT(SIN(u)/u, u, 0, -inf) = -pi/2, the integral becomes:
INT(ê^u·(-a)·SIN(u)/(-a·u), u, 0, -inf)
= -a·INT(ê^u·SIN(u)/u, u, 0, -inf)
= -a·(-pi/2)
= pi·a/2
Therefore, the final answer is pi·a/2.
Now, to save time and make sure you are well-prepared for your exam, you can also use the internet to find helpful resources and practice problems. You can also ask your friends or classmates for help and work together on solving practice questions.
Remember to stay calm and focused, and believe in yourself. Good luck on your examination!
