Question
Why do starts twinkle in the
sky?Solution
It is an example of optical illusion. They appear to twinkle, because light from the stars has to cross several layers of atmosphere with differing refractive indices to reach earth. As the atmospheric conditions in the different layers keep changing, the starts also appear to fade and shine at different times. Hence, option D is correct.
If 0 ≤ θ ≤ 90°, and sin(2 θ +50°) = cos (4 θ + 16°), then what is the value of θ (in degrees)?
sin10˚ x sin20˚ x sin40˚ =?
If (2sin A + cos A) = 3sin A, then find the value of cot A.
If tan 4θ = cot 14θ, then find the value of cos 9θ.
If sin A = 3/5 and cos B = 4/5, where A and B are acute angles, find the value of sin(A + B).
If √3cosec 2x = 2, then the value of x:
If tan θ + cot θ = 2 where 0 < θ < 90 ; find the value of tan30 θ + cot 29 θ.
- If sin (3A − 4B) = (1/2) and cos (A + B) = (√2/2), where 0° < A, B < 90°, then find the value of ‘A’.
If θ is an acute angle and sin θ + cosec θ = 2, then the value of sin2 θ + cosec2 θ is:
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