RRB Group D Model Paper 1 with solutions

(1) The value of
tan 1° tan 2° tan 3° ...........tan 89°
We know that,
tan89° = tan(90° - 1° ) = cot 1°
tan88° = tan(90° - 2° ) = cot 2°
and therefore,
tan1° tan2° tan3° ........ tan45° ..... tan87° tan88° tan89°
= (tan1° cot1° )(tan2° cot2°) (tan3° cot 3° ) .... tan45°
tan 45° = 1
So the value is 1.