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Without using trigonometric tables, evaluate the following (i) (sin 35o cos 55o + cos 35o sin 55 o)/ (cosec2 10o – tan2 80 o) (ii) sin2 34o + sin2 56o + 2 tan18o tan 72o – cot2 30o
Without using trigonometric tables, evaluate the following
(i) (sin 35o cos 55o + cos 35o sin 55 o)/ (cosec2 10o – tan2 80 o)
(ii) sin2 34o + sin2 56o + 2 tan18o tan 72o – cot2 30o
maths | Maths | ML Aggarwal | trigonometric identites
Without using trigonometric tables, evaluate the following
(i) (sin 35o cos 55o + cos 35o sin 55 o)/ (cosec2 10o – tan2 80 o)
(ii) sin2 34o + sin2 56o + 2 tan18o tan 72o – cot2 30o

Given,

(i) (sin 35o cos 55o + cos 35o sin 55 o)/ (cosec2 10o – tan2 80 o)

(ii) sin2 34o + sin2 56o + 2 tan18o tan 72o – cot2 30o

= sin2 34o + sin2 (90o – 34o) + 2 tan18o tan (90o – 18o) – cot2 30o

= [sin2 34o + cos2 34o] + 2 tan18o cot 18o – cot2 30o

= 1 + 2 x 1 – (√3)2

= 1 + 2 – 3

= 0

i

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