Given that (√y/x)⁻⁵ = x‴/y‴ where x ≠ y find the value of m
K Kian McGrath New member Joined Feb 27, 2020 Messages 1 Feb 27, 2020 #1 Given that (√y/x)⁻⁵ = x‴/y‴ where x ≠ y find the value of m
tkhunny Moderator Staff member Joined Apr 12, 2005 Messages 11,339 Feb 27, 2020 #2 I presume it should appear as [math]\left(\sqrt{\dfrac{y}{x}}\right)^{-5} = \dfrac{x^{m}}{y^{m}}[/math] Hint: [math]\sqrt{a} = a^{1/2}[/math]
I presume it should appear as [math]\left(\sqrt{\dfrac{y}{x}}\right)^{-5} = \dfrac{x^{m}}{y^{m}}[/math] Hint: [math]\sqrt{a} = a^{1/2}[/math]
Steven G Elite Member Joined Dec 30, 2014 Messages 14,407 Feb 27, 2020 #3 ... and for example \(\displaystyle (a^\frac{1}{2})^7 = a^{(1/2)(7)} = a^\frac{7}{2}\)
J JeffM Elite Member Joined Sep 14, 2012 Messages 7,874 Feb 27, 2020 #4 The very first thing I would do is a u-substitution, a very helpful technique that for some reason is scarcely taught in algebra. [MATH]\text {Let } u = \dfrac{y}{x} \implies \dfrac{x}{y} = \dfrac{1}{u}.[/MATH] [MATH]\therefore \left ( \sqrt{\dfrac{y}{x}} \right )^{-5} = \dfrac{x^m}{y^m} = \left ( \dfrac{x}{y} \right )^m \implies (\sqrt{u})^{-5} = \left ( \dfrac{1}{u} \right )^m = \dfrac{1}{u^m}.[/MATH] [MATH]\therefore \dfrac{1}{u^m} = (\sqrt{u})^{-5} = \dfrac{1}{(\sqrt{u})^5}.[/MATH] Now what? Last edited: Feb 27, 2020
The very first thing I would do is a u-substitution, a very helpful technique that for some reason is scarcely taught in algebra. [MATH]\text {Let } u = \dfrac{y}{x} \implies \dfrac{x}{y} = \dfrac{1}{u}.[/MATH] [MATH]\therefore \left ( \sqrt{\dfrac{y}{x}} \right )^{-5} = \dfrac{x^m}{y^m} = \left ( \dfrac{x}{y} \right )^m \implies (\sqrt{u})^{-5} = \left ( \dfrac{1}{u} \right )^m = \dfrac{1}{u^m}.[/MATH] [MATH]\therefore \dfrac{1}{u^m} = (\sqrt{u})^{-5} = \dfrac{1}{(\sqrt{u})^5}.[/MATH] Now what?