If sec²A + tan²A = 4/17, then sec4A - tan4A is equal to:
If sin(A + B) = cos(A + B), what is the value of tan A?
\(\, \frac{1 - \tan B}{1 + \tan B} \)
\(\, \frac{1 + \tan B}{1 - \tan B} \)
\(\, \frac{1 + \sec B}{1 - \sec B} \)
\(\, \frac{1 - \mathrm{cosec}\,B}{1 + \mathrm{cosec}\,B} \)