Define a triangle with least perimeter having a fixed vertex (a,b) and other verices at X axis and line y=x(variable). How can i solve it using properties of optics?

Dear twesh

 

point c should be selected such that reflection of point B on line y=x ,and point C and point A must be in straight line.(because straight line give shortest distance)

let the reflection of point B is D(0,X)

but again Ac+Bc =AD will be minimum when line AD will be perpendicular to y Axis

so D=(0,b)

and B (b,0)

so pint C become (b,b)

---

Please feel free to post as many doubts on our discussion forum as you can.
 If you find any question Difficult to understand - post it here and we will get you the answer and detailed solution very quickly.
 We are all IITians and here to help you in your IIT JEE  & AIEEE preparation.

 All the best.
 
Regards,
Askiitians Experts
Badiuddin