Notice in the first step of this computation, we divided the numerator and denominator by {{MATH_57}} (by multiplying them by {{MATH_58}}). This is a ``trick'' that frequently helps in the calculation of limits as {{MATH_59}}, when the function is a fraction. The important point of using {{MATH_60}} here, is that the denominator has degree {{MATH_61}}. When we divide the denominator by {{MATH_62}}, the denominator approaches a nonzero constant. (We're dividing the numerator and denominator by the term type with highest growth order {{CMD_63}}from the denominator{{CMD_64}}.)