#)Giải :
\(\sqrt{13+30\sqrt{2+\sqrt{9+4\sqrt{2}}}}=\sqrt{13+\sqrt{30\sqrt{2+\sqrt{8+2.2\sqrt{2+1}}}}}\)
\(=\sqrt{13+\sqrt{30\sqrt{2+\sqrt{\left(2\sqrt{2}+1\right)^2}}}}=\sqrt{13+\sqrt{30\sqrt{2+2\sqrt{2+1}}}}\)
\(=\sqrt{13+\sqrt{30\sqrt{\left(\sqrt{2}+1\right)^2}}}=\sqrt{13+\sqrt{30\left(\sqrt{2}+1\right)}}=\sqrt{13+\sqrt{30\sqrt{2}+30}}\)
\(\sqrt{13+30\sqrt{2+\sqrt{9+4\sqrt{2}}}}\)
Tinh gia tri bieu thuc
tinh gia tri bieu thut :\(\sqrt{11-2\sqrt{30}}-\sqrt{11+2\sqrt{30}}\)
rut gon \(y=\frac{2x+2}{\sqrt{x}}+\frac{x\sqrt{x}-1}{x-\sqrt{x}}-\frac{x^2+\sqrt{x}}{x\sqrt{x}+x}\)
cmr voi moi gia tri cua x de Y co nghia thi bieu thuc \(\frac{7}{y}\)chi nhan moi gia tri nguyen
\(2\sqrt{3+\sqrt{5-\sqrt{13+\sqrt{48}}}}\)
tinh gia tri bieu thuc
Cho bieu thuc :
A=\(\frac{\sqrt{x}-1}{\sqrt{x}+1}-\frac{\sqrt{x}+3}{\sqrt{x}-2}-\frac{x+5}{x-\sqrt{x}+2}\)
a.Rut gon A
b.Tim gia tri cua x de A <-1
C.Tìm giá trị của x để A nguyen
rut gon roi tinh gia tri cua x de A=-1
\(\sqrt{2}-\sqrt{x+2\sqrt{2x-4}}\)
Bai 1)Cho bieu thuc A=\(\frac{x+y-2\sqrt{xy}}{x-y}\)
a)Tim dieu kien de A co nghia
b)Rut gon A
c)Tinh A biet x=\(3+2\sqrt{2}\)va y=\(3-2\sqrt{2}\)
Bai 2) Cho bieu thuc B=\(\frac{x-3}{\sqrt{x-1}-\sqrt{2}}\)
a)Tim dieu kien de B co nghia
b)Rut gon B
c) Tinh B voi x=\(4\left(2-\sqrt{3}\right)\)
d)Tim x de B co gia tri nho nhat
\(M=\left(\frac{\sqrt{x}+2}{x+2\sqrt{x}+1}-\frac{\sqrt{x}-2}{x-1}\right)N=\frac{\sqrt{x}+1}{\sqrt{x}}\) voi x>0 va x khac 1
a) tim gia tri bieu thuc cua N khi x = 25
b) rut gon S = M.N
c) tim m de S<-1
Cho bieu thuc P = \(\frac{x-\sqrt{x}}{x+\sqrt{x}+1}\) --\(\frac{2x+\sqrt{x}}{\sqrt{x}}\)+\(\frac{2\left(x-1\right)}{\sqrt{x}-1}\)
a) rut gon P
b) tim x de Q=\(\frac{2\sqrt{x}}{P}\)nhan gia tri nguyen