A method and device are provided for processing an input value to provide an output trigonometric function value of the input value. It comprises a method and device for modifying the input value to obtain an approximation value, determining an error value with respect to the approximation value, generating first and second function values with respect to the approximation value, the first and second function values typically being trigonometric function values and typically being obtained from a memory device, determining at least one correction value utilizing a predetermined number of terms of at least one power series, and combining the at least one correction value with the first and second function values to determine the output trigonometric function value.