Toán Lớp 9: ((1 -a*căn bậc hai(a)) /(1 – căn bậc hai(a))+căn bậc hai(a)) *((1 -căn bậc hai(a))/(1 -a))^2
Leave a reply
Register Now
Login
Lost Password
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Toán Lớp 9: ((1 -a*căn bậc hai(a)) /(1 – căn bậc hai(a))+căn bậc hai(a)) *((1 -căn bậc hai(a))/(1 -a))^2
Comments ( 1 )
DK:a \ge 0;a \ne 1\\
\left( {\dfrac{{1 – a\sqrt a }}{{1 – \sqrt a }} + \sqrt a } \right).{\left( {\dfrac{{1 – \sqrt a }}{{1 – a}}} \right)^2}\\
= \left[ {\dfrac{{\left( {1 – \sqrt a } \right)\left( {1 + \sqrt a + a} \right)}}{{1 – \sqrt a }} + \sqrt a } \right].{\left[ {\dfrac{{1 – \sqrt a }}{{\left( {1 – \sqrt a } \right)\left( {\sqrt a + 1} \right)}}} \right]^2}\\
= \left( {1 + 2\sqrt a + a} \right).\dfrac{1}{{{{\left( {\sqrt a + 1} \right)}^2}}}\\
= {\left( {\sqrt a + 1} \right)^2}.\dfrac{1}{{{{\left( {\sqrt a + 1} \right)}^2}}} = 1
\end{array}\)