You can switch the limits around if you like. You WILL get the wrong result.
hi guys can you please help me with this:
If f(x)= cos^4(x)sin(x), evaluate
Would this be correct:
u=cos(x)
du=sin(x)dx

cos(0)=1, cos(pi)=1
Is there a problem that it's decreasing from a to b? Do I need to switch something before I do F(b)F(a)?
When you get the correct result, you should end with "finis" or something more authoritative. The question mark is just really unsatisfying.
If you remain confused, there is nothing wrong with working on the indefinite integral and simply converting back to the original variable and thus managing to use the original units.