Question

Show that:
1) tan 48° tan 23° tan 42° tan 67° = 1
cos 38° cos 52º - sin 38° sin 52° = 0​

Answer 1

Step-by-step explanation:

Tan 48 = Cot (90 - 48 ) = Cot 42

Tan 23 = Cot 67

Tan48 Tan23 Tan 42 Tan 67

= Cot 42 Tan42 Cot67 Tan67 = 1

similarly , Cos38 = Sin52 , Cos52 = Sin38

Answer 2

Step-by-step explanation:

)tan48tan(90-48)tan(90-67)tan67

=tan48cot48cot67tan67

=1

2)cos 38 cos(90-38)-sin38 sin(90-38)

=cos38 sin38-sin38 cos38

=0