Solution :
The value of tan 90 degrees is \(\infty\) or not defined.
Proof :
\(\angle\) A of \(\Delta\) ABC is made large and large until it becomes 90 degrees. As \(\angle\) A gets large and large \(\angle\) C gets smaller and smaller. Side AB goes on decreasing. The point A gets closer to point B. When \(\angle\) C becomes very close to 0 degree. The side AC almost coincide with side BC and side AB becomes to zero.
So, AC = BC and AB = 0
By using trigonometric formulas,
\(tan 90^{\circ}\) = \(perpendicular\over base\) = \(p\over b\)
\(tan 90^{\circ}\) = \(BC\over AB\) = \(BC\over 0\) = \(\infty\) or not defined
Hence, the value of \(tan 90^{\circ}\) = \(\infty\) or not defined.
