buktikan bahwa tan (45+x).tan (45-x) =1

[tex] \tan(45 + x) \times \tan(45 - x) [/tex]
[tex] = \tan(45) + \tan(x) \times \tan(45) - \tan(x) \\ = 1 + x \times 1 - x \\ = 1 \times 1 \\ = 1[/tex]
semoga benar