Evaluate
\sqrt{2}-2\approx -0.585786438
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\frac{\sqrt{30}-2\sqrt{15}}{\sqrt{15}}
To multiply \sqrt{5} and \sqrt{6}, multiply the numbers under the square root.
\frac{\left(\sqrt{30}-2\sqrt{15}\right)\sqrt{15}}{\left(\sqrt{15}\right)^{2}}
Rationalize the denominator of \frac{\sqrt{30}-2\sqrt{15}}{\sqrt{15}} by multiplying numerator and denominator by \sqrt{15}.
\frac{\left(\sqrt{30}-2\sqrt{15}\right)\sqrt{15}}{15}
The square of \sqrt{15} is 15.
\frac{\sqrt{30}\sqrt{15}-2\left(\sqrt{15}\right)^{2}}{15}
Use the distributive property to multiply \sqrt{30}-2\sqrt{15} by \sqrt{15}.
\frac{\sqrt{15}\sqrt{2}\sqrt{15}-2\left(\sqrt{15}\right)^{2}}{15}
Factor 30=15\times 2. Rewrite the square root of the product \sqrt{15\times 2} as the product of square roots \sqrt{15}\sqrt{2}.
\frac{15\sqrt{2}-2\left(\sqrt{15}\right)^{2}}{15}
Multiply \sqrt{15} and \sqrt{15} to get 15.
\frac{15\sqrt{2}-2\times 15}{15}
The square of \sqrt{15} is 15.
\frac{15\sqrt{2}-30}{15}
Multiply -2 and 15 to get -30.
\sqrt{2}-2
Divide each term of 15\sqrt{2}-30 by 15 to get \sqrt{2}-2.
Examples
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{ x } ^ { 2 } - 4 x - 5 = 0
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y = 3x + 4
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\left[ \begin{array} { l l } { 2 } & { 3 } \\ { 5 } & { 4 } \end{array} \right] \left[ \begin{array} { l l l } { 2 } & { 0 } & { 3 } \\ { -1 } & { 1 } & { 5 } \end{array} \right]
Simultaneous equation
\left. \begin{cases} { 8x+2y = 46 } \\ { 7x+3y = 47 } \end{cases} \right.
Differentiation
\frac { d } { d x } \frac { ( 3 x ^ { 2 } - 2 ) } { ( x - 5 ) }
Integration
\int _ { 0 } ^ { 1 } x e ^ { - x ^ { 2 } } d x
Limits
\lim _{x \rightarrow-3} \frac{x^{2}-9}{x^{2}+2 x-3}