Evaluate the following integrals: I. ∫(6t⁴+4t³−t²+1)dt II. ∫(3x²−6x−2)dx. Evaluate the following by method of substitution (i) ∫(3x−4)⁹dx (ii) ∫cos(3x+5)dx

Step 1: Define the limit of a function.
A limit of a function describes the value that a function "approaches" as the input (or independent variable) approaches a certain value. It is a fundamental concept in calculus used to define continuity, derivatives, and integrals.

$\boxed{\text{The limit of a function is the value that the function approaches as the input approaches some value.}}$