在\(\triangle ABC\)中,\(E\)为\(AC\)中点,\(D\)为\(BC\)靠近\(C\)的三等分点,记\( \overrightarrow{AB}= \overrightarrow{a}, \overrightarrow{AC}= \overrightarrow{b}\).
\((1)\)用\( \overrightarrow{a}, \overrightarrow{b}\)表示\( \overrightarrow{AD}, \overrightarrow{BE}\);
\((2)\)求\(BP\):\(PE\),并用\( \overrightarrow{a}, \overrightarrow{b}\)表示\( \overrightarrow{CP}\).