This is a trick is used in my exams to calculate one root of any equation using a non-programmable calculator that are usually allowed during examination.I’ll show how i did it.
Basically its based on Newton Raphson’s formula that i learned in one of my subject.
The formula is as
and in a more generalised form :
now the steps are as under to get the solution :
- Set Ans=1,That can be done by punching in 1 and pressing =.
- Next make an equation ((ANS)-(f(ANS)÷f'(ANS)))
- Punch in =
- Keep punching = until you start getting same result consecutively
Say equation is
f(x) = y = sin x + cos x f'(x) = y' = cos x + sin x
f(ANS) = sin ANS + cos ANS f'(ANS) = cos ANS + Sin ANS
Now making the equation we get
((ANS)-((sin ANS + cos ANS)÷(cos ANS + sin ANS)))
Now we just need to punch in = and we will get the answer.
You may give it a try I used CASIO FX-82 MS calculator by the way..