Cot 70 degree + 4 cos 70 degree
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LHS= cot 70 degree + 4cos 70 degree
= cos 70 degree +4 cos 70 degree sin 70 degree/ sin 70 degree
= cos 70 degree + 2 sin 140 degree / sin 70 degree
= cos 70 degree + 2 sin 40 degree / sin 70 degree
= cos 70 degree + 2 cos 50 degree/ sin 70 degree
= cos 70 degree + cos 50 degree + cos 50 degree / sin 70 degree
= 2 cos 60 degree cos 10 degree + cos 50 degree / sin 70 degree
= cos 10 degree + cos 50 degree / sin 70 degree
= 2 cos 30 degree cos 20 degree / sin 70 degree
= 2 cos 30 degree sin 70 degree / sin 70 degree
= 2 cos 30 degree
= √3
Hence, cot 70 degree + 4 cos 70 degree =√3
Hope it was helpful..........
LHS= cot 70 degree + 4cos 70 degree
= cos 70 degree +4 cos 70 degree sin 70 degree/ sin 70 degree
= cos 70 degree + 2 sin 140 degree / sin 70 degree
= cos 70 degree + 2 sin 40 degree / sin 70 degree
= cos 70 degree + 2 cos 50 degree/ sin 70 degree
= cos 70 degree + cos 50 degree + cos 50 degree / sin 70 degree
= 2 cos 60 degree cos 10 degree + cos 50 degree / sin 70 degree
= cos 10 degree + cos 50 degree / sin 70 degree
= 2 cos 30 degree cos 20 degree / sin 70 degree
= 2 cos 30 degree sin 70 degree / sin 70 degree
= 2 cos 30 degree
= √3
Hence, cot 70 degree + 4 cos 70 degree =√3
Hope it was helpful..........
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