The first two rules both remove root-initial wāw, but their conditions differ.
Word / formMeaning / explanation
يَعِدُthe middle radical has kasrah; Rule 1.
يَهَبُthe middle radical has fatḥah and is itself guttural; Rule 2.
يَضَعُthe middle radical has fatḥah and the final radical is guttural; Rule 2.
A correct derivation must state the relevant vowel and radical position, not merely observe that wāw disappeared.
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Weak-Initial Roots: Elision, Substitution, Assimilation and Short Paradigms
The first two rules both remove root-initial wāw, but their conditions differ.
Word / formMeaning / explanation
يَعِدُthe middle radical has kasrah; Rule 1.
يَهَبُthe middle radical has fatḥah and is itself guttural; Rule 2.
يَضَعُthe middle radical has fatḥah and the final radical is guttural; Rule 2.
A correct derivation must state the relevant vowel and radical position, not merely observe that wāw disappeared.