Hengshui original gold examination paper senior two mathematics answer.
. Sin40 (tan10-tan60) = sin40 (sin10/cos10-root number 3) =sin40[(sin 10- root number 3)/cos1. Cos 10 =- 1 2。 Tan70cos10 (tan60tan20-1) = tan70cos10 (root number 3sin20/cos20-1) = tan70cos65438. ...