When calculate the limits of sequences or functions can obtain the indeterminate forms: 0/0, ∞/∞, 0 * ∞, ∞ - ∞, -∞ + ∞, 1^∞, 0^0, ∞^0. The indeterminate form can equals various numbers or negative, positive infinity. Can not give based on it one solution. Only what can do that calculate the limit from beginning. In such way that not obtain the indeterminate form.