Question

PROVE THAT:---
Tan20° Tan35° Tan45° Tan55° Tan70°=1​

Answer 1

Answer:

L.H.S ==>

Tan20° Tan35° Tan45° Tan55° Tan70

tan(90-70) tan(90-55) tan 45 tan 55 tan 70

cot70 cot55 tan55 tan70 tan45

==> 1/tan70*tan70 1/tan55*tan55 tan45

==> 1*1*tan45

we know that tan45 = 1

so, putting the value of tan45

so, 1*1*1 ==> 1

SO, R.H.S = L.H.S