rút gọn giúp mình vơi các bạn ơi lẹ lên

Report
Question

Please briefly explain why you feel this question should be reported.

Report
Cancel

rút gọn giúp mình vơi các bạn ơi lẹ lên

Answers ( 1 )

  1. Please briefly explain why you feel this answer should be reported.

    Report
    Cancel

    Đáp án:

     

    Giải thích các bước giải:

     ` a) `

    ` ĐKXĐ : x \ne -2 ; x \ne 1 ; x ne +- 1/2 `

    ` ( ( 2 )/( x + 2 ) – ( 2 )/( 1 – x ) ) . ( x^2 – 4 )/( 4x^2 – 1 ) `

    ` = ( 2( 1 – x ) – 2( x + 2 ) )/( ( x + 2 )( 1 – x ) ) . ( ( x + 2 )( x – 2 ) )/( ( 2x – 1 )( 2x + 1 ) ) `

    ` = ( 2 – 2x – 2x – 4 )/( 1 – x ) . ( x – 2 )/( ( 2x + 1 )( 2x – 1 ) ) `

    ` = ( -4x – 2 )/( 1 – x ) . ( x – 2 )/( ( 2x + 1 )( 2x – 1 ) ) `

    ` = ( -2( 2x + 1 ) )/( 1 – x ) . ( x – 2 )/(( 2x + 1 )( 2x – 1 ) ) `

    ` = ( -2( x – 2 ) )/( ( 1 – x )( 2x + 1 ) ) `

    ` b) `

    ` ĐKXĐ : x \ne 1 `

    ` ( x^3 + 1 )/( 1 – x^3 ) + ( x )/( x – 1 ) – ( x + 1 )/( x^2 + x + 1 ) `

    ` = ( x^3 + 1 )/( 1 – x^3 ) – ( x )/( 1 – x  ) – ( x + 1 )/( x^2 + x + 1 ) `

    ` = ( x^3 + 1 )/( ( 1 – x )( x^2 + x + 1 )) – ( x( x^2 + x + 1 ) )/( ( 1 – x )( x^2 + x + 1 ) ) – ( ( x + 1 )( 1 – x ) )/( ( 1 – x )( x^2 + x + 1 ) ) `

    ` = ( x^3 + 1 – x^3 – x^2 – x – 1 + x^2 )/( ( 1 – x )( x^2 + x + 1 ) ) `

    ` = ( -x )/( 1 – x^3 ) `

    ` c) `

    ` ĐKXĐ : x \ne +- 1 `

    ` 1 + ( x^3 – x )/( x^2 + 1 ) . ( ( 1 )/( 1 – x ) – ( 1 )/( 1 – x^2 ) ) `

    ` = 1 + ( x( x^2 – 1 ) )/( x^2 + 1 ) . ( ( 1 )/( 1 – x ) – ( 1 )/( ( 1 – x )( 1 + x ) ) ) `

    ` = 1 + ( -x( x + 1 )( 1 – x ) )/( x^2 + 1 ) . ( 1 + x – 1 )/( ( 1 – x )( 1 + x ) ) `

    ` = 1 + ( -x^2 )/( x^2 + 1 ) `

    ` = ( x^2 + 1 – x^2 )/( x^2 + 1 ) `

    ` = ( 1 )/( x^2 + 1 ) `

Leave an answer

Browse

By answering, you agree to the Terms of Service and Privacy Policy.