Can someone please check where I made a mistake 20b only please (1 Viewer)

[kpad5991]

The answer is log (2+root 3)

https://imgur.com/gallery/pM1ps

 

[jathu123]

between your 6th last and 5th last step
log(a+b) =/= log(a)+log(b)
ie, you cant expand it like a normal algebraic term, its like how you cant expand sin(a+b) into sin(a)+sin(b)

so continuing, ln(8+√48)-ln4
= ln(8+4√3)-ln4
=ln((8+4√3)/4)
=ln(2+√3)

 

[kpad5991]

between your 6th last and 5th last step
log(a+b) =/= log(a)+log(b)
ie, you cant expand it like a normal algebraic term, its like how you cant expand sin(a+b) into sin(a)+sin(b)

so continuing, ln(8+√48)-ln4
= ln(8+4√3)-ln4
=ln((8+4√3)/4)
=ln(2+√3)

Thank you