Can the person praying behind the imam read something from the Mushaf other than what the imam is reciting?
Question

                I pray behind the imam in Taraweeh prayers, but after saying ameen and reciting al-Faatihah, I read from the Mushaf that is in my hand, for my own completion of the Qur’aan, then I follow the imam in the rest of the prayer. Is it permissible for me to read from the Mushaf after al-Faatihah, knowing that I am reading a different soorah than the imam?.
Praise be to Allah.
    Firstly: 

    What the person praying behind the imam should do is to 
    recite al-Faatihah then listen attentively to the recitation of his imam. It 
    is not permissible for him to recite anything more than al-Faatihah, whether 
    he recites it from memory or from the Mushaf. 

    Allaah has commanded worshippers and others to listen 
    attentively when the Qur’aan is recited to them. Allaah says (interpretation 
    of the meaning): 
“So, when the Qur’aan is 
    recited, listen to it, and be silent that you may receive mercy”

    [al-A’raaf 7:204]

    A similar command was issued by the Prophet  (peace and 
    blessings of Allaah be upon him). It was narrated that Abu Moosa al-Ash’ari 
    (may Allaah be pleased with him) said: The Messenger of Allaah  (peace 
    and blessings of Allaah be upon him) said: “The imam has been appointed to 
    be followed, so when he says takbeer, then say takbeer, and when he recites, 
    then listen attentively.” Narrated by Muslim, 404. 

    No exception is made from that apart from the recitation of 
    al-Faatihah only. 

    It was narrated that ‘Ubaadah ibn al-Saamit (may Allaah be 
    pleased with him) said: We were behind the Messenger of Allaah  (peace 
    and blessings of Allaah be upon him) in Fajr prayer, and the Messenger of 
    Allaah  (peace and blessings of Allaah be upon him) recited and the 
    recitation became difficult for him. When he had finished he said: “Perhaps 
    you were reciting behind your imam?” We said: Yes, that is so, O Messenger 
    of Allaah. He said: “Do not do that, except for the Opening of the Book 
    (al-Faatihah), for there is no prayer for the one who does not recite it.” 
    Narrated by Abu Dawood, 823; classed as saheeh by Shaykh Ibn Baaz in his 
    Fataawa, 11/221. 

    Shaykh ‘Abd al-‘Azeez ibn Baaz (may Allaah have mercy on him) 
    said: 

    It is not permissible for the one who is praying behind the 
    imam in a prayer in which Qur’aan is recited out loud to recite anything 
    more than al-Faatihah, rather after that he must remain silent and listen 
    attentively to the recitation of the imam, because the Prophet  (peace 
    and blessings of Allaah be upon him) said: “Perhaps you were reciting behind 
    your imam?” We said: Yes, that is so, O Messenger of Allaah. He said: “Do 
    not do that, except for the Opening of the Book (al-Faatihah), for there is 
    no prayer for the one who does not recite it.” And because Allaah says 
    (interpretation of the meaning): “So, when the Qur’aan is recited, listen 
    to it, and be silent that you may receive mercy”, and the Prophet  
    (peace and blessings of Allaah be upon him) said: “When he recites, then 
    listen attentively.” 

    With regard to the exception that is made with regard to 
    al-Faatihah only, that is because of the hadeeth quoted above, and because 
    the Prophet  (peace and blessings of Allaah be upon him) said: “There is 
    no prayer for the one who does not recite the Opening of the Book.” Saheeh – 
    agreed upon. End quote. 

    Majmoo’ Fataawa al-Shaykh Ibn Baaz, 
    11/234 

    Secondly: 

    In the answer to question no. 
    52876 , it says that the person who is praying behind the imam should not 
    hold the Mushaf behind his imam, and that holding it is contrary to the 
    Sunnah. This applies if he is following the recitation of his imam. But if 
    he is carrying the Mushaf and reading something other than what his imam is 
    reciting, then this is haraam, as stated above, because it is not 
    permissible for the person who is praying behind the imam in a prayer in 
    which Qur’aan is recited out loud to recite anything more than al-Faatihah.

    And Allaah knows best.