TLS signed “A. Einstein,” one page, 8.5 x 11, August 2, 1938. Einstein (who, given some minor typos, evidently took the time to type this letter himself!) gives the nod to a trigonometry solution submitted to him by a curious student. In full: “the solution is good. It is only to add that the roots must be taken positiv [sic].” In fine condition, with intersecting folds, one passing through the middle of the signature, and light toning. Accompanied by the original mailing envelope and ‘The Problem,’ drawn out in pencil, to which Einstein was responding. A unique example, for any Einstein enthusiast! RRAuction COA.
