- Homework Statement
- The question is in Attempt at a solution
- Homework Equations
So the resistance is coming to be negative.Can anyone tell me my mistake.Thanks.
Formally your answer is correct. Input source impedance is (3||6 Ohm)=2 Ohm, therefore from matching theorem your load must be also 2 Ohm for maximal transferred power. You just need to trim negative resistance answer to closest physical value (i.e. 0).
Your error is in assuming all minima are local minima, i.e. where a gradient is zero.So the resistance is coming to be negative.Can anyone tell me my mistake.Thanks.
Can you please explain me how can i do that here means how can i find the range of R.Your error is in assuming all minima are local minima, i.e. where a gradient is zero.
Sometimes the global minimum occurs at one end of the valid range. In general, you should check the extremities of the range even if you do find a local minimum.
The range of R should either be given by the problem(for example in this problem it could have been given that the variable resistor is in the range for example ##[4,404]##) or can be logically inferred like for example in this problem the range of R is logically inferred to be ##[0,+\infty)##. So you look for maximum or minimum at the end points and how to prove that the value at the end point is a maximum (or minimum).Can you please explain me how can i do that here means how can i find the range of R.
You worked out the derivative. You looked for zeros. Good. Now check the value of the function and the derivative at the end points.