Question

tan131*. tan132*. tan133*. ..........up to tan139* =

Answer 1

tan131= tan(90+41)= cot41
tan132 =tan(90+42)= cot42

similarly
tan139=tan(90+49)= cot49

Hence the series will form
cot41.cot42.....cot49

we know that if A+B=90° ,,
then CotA. CotB= 1

{{or you can say that cot49=cot(90-49)=tan49
so cot49.tan49=1}


THEREFORE

cot41.cot49=1
cot42.cot48=1
cot43.cot47=1
cot44.cot46=1
cot45=1

HENCE the value of cot41.cot42.....cot49=1