Electrical FE /EIT Exam Prep - Electronics 3: Op-Amp Input Resistance

[@LarmWiqlid]

Isn't input resistance the path from the input to ground? If so wouldn't the correct answer be: Rin = R1 || (R2 + R3) = 7.5kOhms

[@bdurrani34]

both Vin should be canceled out

[@bdurrani34]

the math doesnt work

[@AnasAsifSA]

it does work. you cant cancel both Vin as they are in an arithmetic sum (high school algebra)