Tính giá trị :
\(F=4^{3+\sqrt{2}}.2^{1-\sqrt{2}}.2^{-3-\sqrt{2}}\)
1/Cho \(x+y+z+\sqrt{xyz}=4\)
Tính giá trị biểu thức \(T=\sqrt{x\left(4-y\right)\left(4-z\right)}+\sqrt{y\left(4-x\right)\left(4-z\right)}+\sqrt{z\left(4-x\right)\left(4-y\right)}-\sqrt{xyz}\)
2/Cho \(x=\sqrt[3]{4+2\sqrt{2}}+\sqrt[3]{4-2\sqrt{2}}\)
Tính giá trị biểu thức \(F=\left(x^3-6x-10\right)^{2019}\)
3/Cho \(x=\sqrt{\frac{1}{2\sqrt{3}-2}-\frac{3}{2\sqrt{3}+2}}\)
Tính giá trị biểu thức \(P=x^2+\frac{x-1}{2}\)
4/Cho \(x=\sqrt{28-10\sqrt{3}}\)
Tính giá trị biểu thức \(F=\frac{2x^4-21x^3+55x^2-32x-4012}{x^2-10x+20}\)
Với \(x=-\frac{2\sqrt{3+\sqrt{5-\sqrt{13+\sqrt{48}}}}}{\sqrt{6}+\sqrt{2}}\) Tính giá trị của :\(f\left(x\right)=1+x^2+x^3+x^4+....+x^{2016}\)
\(x=-\frac{2\sqrt{3+\sqrt{5-\sqrt{12+2\sqrt{12}+1}}}}{\sqrt{6}+\sqrt{2}}\)
\(x=-\frac{2\sqrt{3+\sqrt{5-\sqrt{\left(\sqrt{12}+1\right)^2}}}}{\sqrt{6}+\sqrt{2}}\)
\(x=-\frac{2\sqrt{3+\sqrt{5-\sqrt{12}-1}}}{\sqrt{6}+\sqrt{2}}\)
\(x=-\frac{2\sqrt{3+\sqrt{4-2\sqrt{3}}}}{\sqrt{6}+\sqrt{2}}\)
\(x=-\frac{2\sqrt{3+\sqrt{3-2\sqrt{3}+1}}}{\sqrt{6}+\sqrt{2}}\)
\(x=-\frac{2\sqrt{3+\sqrt{\left(\sqrt{3}-1\right)^2}}}{\sqrt{6}+\sqrt{2}}\)
\(x=-\frac{2\sqrt{3+\sqrt{3}-1}}{\sqrt{6}+\sqrt{2}}\)
\(x=-\frac{2\sqrt{2+\sqrt{3}}}{\sqrt{2}\left(\sqrt{3}+1\right)}\)
\(x=-\frac{\sqrt{2}\sqrt{2+\sqrt{3}}}{\left(\sqrt{3}+1\right)}\)
\(x=-\frac{\sqrt{4+2\sqrt{3}}}{\sqrt{3}+1}\)
\(x=-\frac{\sqrt{3+2\sqrt{3}+1}}{\sqrt{3}+1}\)
\(x=-\frac{\sqrt{\left(\sqrt{3}+1\right)^2}}{\sqrt{3}+1}\)
\(x=-\frac{\sqrt{3}+1}{\sqrt{3}+1}=-1\)
đến đây dễ òi nhé
B 4. Tính giá trị của các biểu thức:
a) 2\(\sqrt{5}\) -\(\sqrt{20}\)+3\(\sqrt{45}\)-3\(\sqrt{500}\) b) 2\(\sqrt{7}\)-3\(\sqrt{28}\)-\(\dfrac{1}{4}\)\(\sqrt{63}\)-2\(\sqrt{252}\)
c) 2\(\sqrt{3}\) -\(\sqrt{12}\)+3\(\sqrt{108}\) -3\(\sqrt{75}\) d)2\(\sqrt{6}\) -3\(\sqrt{24}\) +\(\dfrac{1}{5}\) \(\sqrt{150}\) -5\(\sqrt{3600}\)
a: \(=2\sqrt{5}-2\sqrt{5}+9\sqrt{5}-30\sqrt{5}=-21\sqrt{5}\)
b: \(=2\sqrt{7}-6\sqrt{7}-\dfrac{3}{4}\sqrt{7}-8\sqrt{7}=-\dfrac{51}{4}\sqrt{7}\)
Tính giá trị của biểu thức \(M=\frac{1}{2\sqrt{1}+1\sqrt{2}}+\frac{1}{3\sqrt{2}+2\sqrt{3}}+\frac{1}{4\sqrt{3}+3\sqrt{4}}+...+\frac{1}{121\sqrt{120}+120\sqrt{121}}\)
Với \(k\in N;k\ne0\) ta có :
\(\frac{1}{\left(k+1\right)\sqrt{k}+k\sqrt{\left(k+1\right)}}=\frac{1}{\sqrt{k\left(k+1\right)}\left(\sqrt{k}+\sqrt{k+1}\right)}\)
\(=\frac{\sqrt{k+1}+\sqrt{k}}{\sqrt{k\left(k+1\right)}\left(\sqrt{k+1}-\sqrt{k}\right)\left(\sqrt{k+1}+\sqrt{k}\right)}=\frac{\sqrt{k+1}-\sqrt{k}}{\sqrt{k\left(k+1\right)}}\)
\(=\frac{1}{\sqrt{k}}-\frac{1}{\sqrt{k+1}}\)
Áp dụng ta có :
\(M=\frac{1}{\sqrt{1}}-\frac{1}{\sqrt{2}}+\frac{1}{\sqrt{2}}-\frac{1}{\sqrt{3}}+....+\frac{1}{\sqrt{120}}-\frac{1}{\sqrt{121}}=1-\frac{1}{11}=\frac{10}{11}\)
\(\frac{1}{2\sqrt{1}+1\sqrt{2}}+\frac{1}{3\sqrt{2}+2\sqrt{3}}+\frac{1}{4\sqrt{3+3\sqrt{4}}}+...+\frac{1}{2017\sqrt{2016}+2016\sqrt{2017}}\)
Tính giá trị của biểu thức .
\(1-\frac{1}{\sqrt{2}}+\frac{1}{\sqrt{2}}-\frac{1}{\sqrt{3}}+...+\frac{1}{\sqrt{2016}}-\frac{1}{\sqrt{2017}}=1-\frac{1}{\sqrt{2007}}=\frac{\sqrt{2007}-1}{\sqrt{2007}}\)
Tính giá trị của: \(A=\dfrac{1}{2}\sqrt{\dfrac{1}{2}}-\dfrac{3}{2}\sqrt{2}+\dfrac{4}{5}.\sqrt{2\sqrt{2}}\)
\(A=\dfrac{1}{2}\cdot\dfrac{\sqrt{2}}{2}-\dfrac{3}{2}\cdot\sqrt{2}+\dfrac{4}{5}\cdot\sqrt{2}\cdot\sqrt{\sqrt{2}}\)
\(=\sqrt{2}\left(\dfrac{1}{4}-\dfrac{3}{2}+\dfrac{4}{5}\sqrt{\sqrt{2}}\right)=\left(-\dfrac{5}{4}+\dfrac{4}{5}\sqrt[4]{2}\right)\cdot\sqrt{2}\)
1) Tính giá trị biểu thức:
a)A=\(\sqrt{4+2\sqrt{3}}\)
b) B=\(\dfrac{1}{2-\sqrt{3}}+\dfrac{1}{2+\sqrt{3}}\)
2) Giai phương trình: \(\sqrt{4x-12}+\sqrt{x-3}-\dfrac{1}{3}\sqrt{9x-27}=8\)
3)Tìm x: 2x2-4=8
`a)A=\sqrt{4+2sqrt3}`
`=\sqrt{3+2sqrt3+1}`
`=sqrt{(sqrt3+1)^2}`
`=sqrt3+1`
`B)1/(2-sqrt3)+1/(2+sqrt3)`
`=(2+sqrt3)/(4-3)+(2-sqrt3)/(4-3)`
`=2+sqrt3+2-sqrt3`
`=4`
`\sqrt{4x-12}+sqrtx{x-3}-1/3sqrt{9x-27}=8`
`đk:x>=3`
`pt<=>2sqrt{x-3}+sqrt{x-3}-sqrt{x-3}=8`
`<=>2sqrt{x-3}=8`
`<=>sqrt{x-3}=4`
`<=>x-3=16`
`<=>x=19`
Vậy `S={19}`
`a)A=\sqrt{4+2sqrt3}`
`=\sqrt{3+2sqrt3+1}`
`=sqrt{(sqrt3+1)^2}`
`=sqrt3+1`
`B)1/(2-sqrt3)+1/(2+sqrt3)`
`=(2+sqrt3)/(4-3)+(2-sqrt3)/(4-3)`
`=2+sqrt3+2-sqrt3`
`=4`
`\sqrt{4x-12}+sqrt{x-3}-1/3sqrt{9x-27}=8`
`đk:x>=3`
`pt<=>2sqrt{x-3}+sqrt{x-3}-sqrt{x-3}=8`
`<=>2sqrt{x-3}=8`
`<=>sqrt{x-3}=4`
`<=>x-3=16`
`<=>x=19`
Vậy `S={19}`
tính giá trị biểu thức
13-\(\sqrt{\left(\sqrt{2}-3\right)^2}\)
\(\sqrt{3-2\sqrt{2}}\)-\(\sqrt{6-4\sqrt{2}}\)
\(13-\sqrt{\left(\sqrt{2}-3\right)^2}\)
=13-/\(\sqrt{2}\)-3/
=13-(3-\(\sqrt{2}\))
=13-3+\(\sqrt{2}\)
=10\(\sqrt{2}\)
\(\sqrt{3-2\sqrt{2}}-\sqrt{6-4\sqrt{2}}\)
\(=\sqrt{2-2\sqrt{2}+1}-\sqrt{4-2.2\sqrt{2}+2}\)
\(=\sqrt{\left(\sqrt{2}-1\right)^2}-\sqrt{\left(2-\sqrt{2}\right)^2}\)
\(=\sqrt{2}-1-2+\sqrt{2}\)
\(=2\sqrt{2}-3\)
1) \(13-\sqrt{\left(\sqrt{2}-3\right)^2}=13-\left|\sqrt{2}-3\right|=13+\sqrt{2}-3=10+\sqrt{2}\)
2) \(\sqrt{3-2\sqrt{2}}-\sqrt{6-4\sqrt{2}}=\sqrt{\left(\sqrt{2}-1\right)^2}-\sqrt{\left(2-\sqrt{2}\right)^2}=\left|\sqrt{2}-1\right|-\left|2-\sqrt{2}\right|=\sqrt{2}-1-2+\sqrt{2}=2\sqrt{2}-3\)
1) 13−√(√2−3)2=13−∣∣√2−3∣∣=13+√2−3=10+√213−(2−3)2=13−|2−3|=13+2−3=10+2
2) √3−2√2−√6−4√2=√(√2−1)2−√(2−√2)2=∣∣√2−1∣∣−∣∣2−√2∣∣=√2−1−2+√2=2√2−3
tính giá trị của hàm số
a) y= f(x)= x2 +x-2 tại x0 =\(\dfrac{1}{2}\)
b)y=f(x)=\(\dfrac{2\sqrt{3}}{x^2+1}\) tại x0 =\(\sqrt{3}\)
a: \(f\left(\dfrac{1}{2}\right)=\left(\dfrac{1}{2}\right)^2+\dfrac{1}{2}-2=\dfrac{1}{4}+\dfrac{1}{2}-2=\dfrac{3}{8}-2=\dfrac{3-16}{8}=-\dfrac{13}{8}\)
b: \(f\left(\sqrt{3}\right)=\dfrac{2\sqrt{3}}{\left(\sqrt{3}\right)^2+1}=\dfrac{2\sqrt{3}}{4}=\dfrac{\sqrt{3}}{2}\)