Question

( frac{cot 54^{circ}}{tan 36^{circ}}+frac{tan 20^{circ}}{cot 70^{circ}} )
( frac{cot left(90-36^{circ}right)}{tan 36^{circ}}+frac{tan 20^{circ}}{cos left(90^{circ}-20^{circ}right)} )
( =frac{tan 36^{circ}}{tan 36^{circ}}+frac{tan 20^{circ}}{tan 20^{circ}} )
( =1+1=2 tan ^{2} )

# 86. cot 54°tan 20° tan 36° cot 70°

Solution