How to find square root without pen-copy used in mind ? Please give me trick.
Practice more and more u definitely learn the roots then can solve questions very fast in exams
By log book
Hav basic knowlege of square root n guess
U can guess the square root. And options in question in jee will be nearby. There may be many methods if u practice u can do in head without pen and paper like linear appx.
F(a+h) = F(a) + h*F'(a).
You can work out sqrt(30). Since sqrt(25)=5.
Sqrt(30)= sqrt(25+5) = sqrt(25) + 5 * 1/(2sqrt(25)) = 5 + 5/(2*5) = 5 + 1/2 = 5.5
This can be done in head