If A is a 3×3 matrix and a1 +2a2 −a3 = 0, then A must be singular.

A、1

B、2

C、3

D、4

  (A)(A^*)^*=|A|^n-1A  (B)(A^*)^*=|A|ⁿ⁺¹A

  (C)(A^*)^*=|A|^n-2A  (D)(A^*)^*=|A|ⁿ⁺²A

A、a=1,b=-2

B、a=1,b=3

C、a=3,b=-1

D、a=3,b=1

A、R(A)=n-2

B、R(A)=n-1

C、R(A) <n-2>

D、R(A) <n-1>

1 “Imagine” is a song co-written and performed by English musician John Lennon. The best-selling single of his solo career, its lyrics encourage the listener to imagine a world at peace without the barriers of borders or the divisions of religion and nationality and to consider the possibility that the whole of humanity would live unattached to material possessions. Lennon hoped that the softer and beautiful melody would bring the song to a wider audience, who hopefully would listen to his message. 2 Lennon later felt that this song should have been a Lennon/Ono (Lennon’s wife, a Japanese) collaboration. Shortly before his death, Lennon said that much of the song’s “lyric and content” came from his wife Yoko Ono, and in 2017, she received a co-writing credit. He got the initial idea from Yoko’s book Grapefruit, which is a book of instructions, with things like “Imagine the sky crying...” or “Imagine you're a cloud.” 3 Some people have wondered if Lennon included a message in the video for this song as well. In the video, Lennon is dressed as a cowboy and Yoko Ono is dressed as an Indian squaw. 4 Lennon wrote this on a brown Steinway upright piano. In 2000, George Michael paid over $2 million for the piano that Lennon wrote this on, and then returned it to the Beatles museum in Liverpool. John’s piano has since been “on tour” to various world locations promoting peace. 5 This was not released as a single in the UK until 1975, when it hit #6. Shortly after Lennon’s death in 1980, it was re-released in the UK and hit #1. It was replaced at #1 by Lennon’s “Woman,” marking the first time an artist replaced himself on top of the UK According to this passage, which of the following is NOT true?

A、Imagine hit #1 at its first release.

B、In 1980, Imagine hit #1 in UK.

C、John Lennon’s Imagine, Woman hit #1 in UK.

D、Beatles’ She Loves You and I Want To Hold Your Hand all hit #1 in UK too.

1“Imagine” is a song co-written and performed by English musician John Lennon. The best-selling single of his solo career, its lyrics encourage the listener to imagine a world at peace without the barriers of borders or the divisions of religion and nationality and to consider the possibility that the whole of humanity would live unattached to material possessions. Lennon hoped that the softer and beautiful melody would bring the song to a wider audience, who hopefully would listen to his message. 2 Lennon later felt that this song should have been a Lennon/Ono (Lennon’s wife, a Japanese) collaboration. Shortly before his death, Lennon said that much of the song’s “lyric and content” came from his wife Yoko Ono, and in 2017, she received a co-writing credit. He got the initial idea from Yoko’s book Grapefruit, which is a book of instructions, with things like “Imagine the sky crying...” or “Imagine you're a cloud.” 3 Some people have wondered if Lennon included a message in the video for this song as well. In the video, Lennon is dressed as a cowboy and Yoko Ono is dressed as an Indian squaw. 4 Lennon wrote this on a brown Steinway upright piano. In 2000, George Michael paid over $2 million for the piano that Lennon wrote this on, and then returned it to the Beatles museum in Liverpool. John’s piano has since been “on tour” to various world locations promoting peace. 5 This was not released as a single in the UK until 1975, when it hit #6. Shortly after Lennon’s death in 1980, it was re-released in the UK and hit #1. It was replaced at #1 by Lennon’s “Woman,” marking the first time an artist replaced himself on top of the UK charts since The Beatles followed “She Loves You” with “I Want To Hold Your Hand.” In Imagine’s video, why is Lennon dressed as a cowboy and Yoko Ono dressed as an Indian squaw?

A、This could be a kind of message about all cultures getting along.

B、This could be a kind of message of love.

C、This could be a kind of message of antigovernment.

D、This could be a kind of message of antireligious.

A、123

B、0124

C、5334

D、70