(1)计算:11+2+12+3+13+4+…199+100.

1个回答

  • 解题思路:(1)先把分母有理化,再进一步合并化简即可;

    (2)先化简代数式,再进一步代入求得数值即可.

    (1)原式=

    2-1+

    3-

    2+

    4-

    3+…+

    100-

    99

    =-1+10

    =9;

    (2)原式=

    (x+3)(x−2)

    x•

    x(x−2)

    x+3-

    x2−4x+4−2(x−2)

    x2−4x+x2−4x

    4

    =x2-4x+4-

    x2−4x+2−(x−2)

    x2−4x

    2

    =

    x2−4x+6+(x−2)

    x2−4x

    2;

    x=

    a+

    1

    a

    ∴x=a+2+

    1

    a

    ∴原式=

    1

    2[(a+

    1

    a)2+2+(a+

    1

    a)(a-

    1

    a)]=a2+2;

    点评:

    本题考点: 二次根式的化简求值.

    考点点评: 此题考查了分式的化简求值,熟练掌握运算法则是解本题的关键.