(1/2-căn5+2/căn5+căn3):1/tất cả căn21-12can3

0 bình luận về “(1/2-căn5+2/căn5+căn3):1/tất cả căn21-12can3”

1. Đáp án:

   `(1/(2-sqrt5)+2/(sqrt5+sqrt3)):1/sqrt{21-12sqrt3}`

   `=((2+sqrt5)/(4-5)+(2(sqrt5-sqrt3))/(5-3)):1/sqrt{12-2.2sqrt{3}.3+9}`

   `=(-(2+sqrt5)+2(sqrt5-sqrt3)):1/sqrt{(2sqrt3-3)^2}`

   `=(-2-sqrt5+2sqrt5-2sqrt3):1/(2sqrt3-3)`

   `=(sqrt5-2sqrt3-2)(2sqrt3-3)`

   `=2sqrt{15}-3sqrt5-12+6sqrt3-4sqrt3+6`

   `=2sqrt{15}-3sqrt5+2sqrt3-6`

   Bình luận