KnowledgeBoat Logo
|

Mathematics

If 32 log a+23 log b 1=0\dfrac{3}{2} \text{ log a} + \dfrac{2}{3} \text{ log b } - 1 = 0, find the value of a9.b4

Logarithms

22 Likes

Answer

Given,

32 log a+23 log b 1=0log a32+log b23=1log a32+log b23=log 10log (a32×b23)=log 10(a32×b23)=10\Rightarrow \dfrac{3}{2} \text{ log a} + \dfrac{2}{3} \text{ log b } - 1 = 0 \\[1em] \Rightarrow \text{log a}^{\dfrac{3}{2}} + \text{log b}^{\dfrac{2}{3}} = 1 \\[1em] \Rightarrow \text{log a}^{\dfrac{3}{2}} + \text{log b}^{\dfrac{2}{3}} = \text{log 10} \\[1em] \Rightarrow \text{log } (a^{\dfrac{3}{2}} \times b^{\dfrac{2}{3}}) = \text{log 10} \\[1em] \Rightarrow (a^{\dfrac{3}{2}} \times b^{\dfrac{2}{3}}) = 10

Cubing and then squaring both sides, we get :

[(a32×b23)3]2=[(10)3]2(a32×b23)6=106a32×6.b23×6=106a182.b123=106a9.b4=106.\Rightarrow [(a^{\dfrac{3}{2}} \times b^{\dfrac{2}{3}})^3]^2 = [(10)^3]^2 \\[1em] \Rightarrow (a^{\dfrac{3}{2}} \times b^{\dfrac{2}{3}})^6 = 10^6 \\[1em] \Rightarrow a^{\dfrac{3}{2} \times 6}.b^{\dfrac{2}{3} \times 6} = 10^6 \\[1em] \Rightarrow a^{\dfrac{18}{2}}.b^{\dfrac{12}{3}} = 10^6 \\[1em] \Rightarrow a^9.b^4 = 10^6.

Hence, a9.b4 = 106.

Answered By

13 Likes


Related Questions