(1) The value of tan1° tan2° tan3° ...........tan89° We know that, tan89°= tan(90°- 1° ) =cot1° tan88°= tan(90°- 2° ) =cot2° and therefore, tan1° tan2° tan3° ........tan45°.....tan87° tan88° tan89° =(tan1° cot1° )(tan2° cot2° ) (tan3° cot3° )....tan45° tan45°= 1 So the value is 1.