Mathematics
Without using trigonometrical tables, evaluate the following :
sin2 28° + sin2 62° - tan2 45°
Trigonometrical Ratios
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Answer
Solving,
⇒ sin2 28° + sin2 62° - tan2 45°
⇒ sin2 28° + sin2 (90° - 28°) - tan2 45°
⇒ sin2 28° + cos2 28° - 1 [∵ sin (90 - θ) = cos θ]
⇒ 1 - 1 [∵ sin2 θ + cos2 θ]
⇒ 0.
Hence, sin2 28° + sin2 62° - tan2 45° = 0.
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