Question

What is the mirror formula for curved mirrors?

The inverse of f equals the inverse of d Subscript o Baseline times the inverse of d Subscript I Baseline.
The inverse of f plus the inverse of d Subscript o Baseline equals the inverse of d Subscript I Baseline.
The inverse of f equals the inverse of d Subscript o Baseline plus the inverse of d Subscript I Baseline.
The inverse of f equals the inverse of d Subscript o Baseline minus the inverse of d Subscript I Baseline.

Answer 1

Correct answer: "The inverse of f equals the inverse of d_o plus the inverse of d_i."

In formula form: 1/f = 1/do + 1/di.

(For a spherical mirror f = R/2. Use the usual sign convention: for a concave mirror f positive, for a convex mirror f negative; object distances are usually positive for real objects, image distances positive for real images, etc.)