Question
Who proposed the 'Law of Octaves' in the periodic
classification of elements?Solution
The 'Law of Octaves' was proposed by John Newlands in 1865. According to this law, elements arranged in increasing order of atomic weights exhibit similar properties at every eighth element.
cot 13Ëš Â
 cot 14˚  ...If (sin A + cos A) = √3 cos (90° - A), then find the value of cot A.
- If 2cos²A + 3sin²A = 13/5, then find the value of (sec²A - 1)
If sin (2x + 50) o = cos (2y - 50) o, such that, 0o < x + y < 90o, then find the value of tan(x + y) .
- If sin(A + B) = √3/2 and cos(A + 2B) = 0, where 0° < A, B < 90°, then find the value of tan(2A).
If cos 2A = 1, then find cos A
What is the simplified value of the given expression?
3(sin² 50° + sin² 40°) + 6sin 30° - (3sec 60° + cot 45°)
Find the value of `1/2`  cosec 10  - `2/(cosec 70)`  ?
Find the maximum value of 20 sin A + 9 cos A.
- If sin (3A − 4B) = (1/2) and cos (A + B) = (√2/2), where 0° < A, B < 90°, then find the value of ‘A’.