Show that : tan 10° tan 15° tan 75° tan 80° = 1

Question

KnowledgeBoat · Accepted Answer

tan 10° tan 15° tan 75° tan 80° = 1 L.H.S. = tan 10° tan 15° tan 75° tan 80° = tan (90° - 80°) tan (90° - 75°) tan 75° tan 80° = cot 80° cot 75° tan 75° tan 80° = = = 1 R.H.S. = 1 ∴ L.H.S. = R.H.S. Hence, tan 10° tan 15° tan 75° tan 80° = 1.

Mathematics

Show that :
tan 10° tan 15° tan 75° tan 80° = 1

Trigonometric Identities

Related Questions

Evaluate :
cos² 25° - sin² 65° - tan² 45°

Show that :
sin 42° sec 48° + cos 42° cosec 48° = 2

Express the following in terms of angles between 0° and 45° :
sin 59° + tan 63°

Mathematics

Show that :tan 10° tan 15° tan 75° tan 80° = 1

Trigonometric Identities

Related Questions

Evaluate :cos2 25° - sin2 65° - tan2 45°

Show that :sin 42° sec 48° + cos 42° cosec 48° = 2

Express the following in terms of angles between 0° and 45° :sin 59° + tan 63°

Show that :
tan 10° tan 15° tan 75° tan 80° = 1

Evaluate :
cos² 25° - sin² 65° - tan² 45°

Show that :
sin 42° sec 48° + cos 42° cosec 48° = 2

Express the following in terms of angles between 0° and 45° :
sin 59° + tan 63°