Language is remarkable, except under the extreme constraints of mathematics and logic, it never can talk only about what it's supposed to talk about but is always spreading around.

If I am given a formula and I am ignorant of its meaning, it cannot teach me anything, but if I already know it what does the formula teach me?

M4Math helped me a lot.

Thanks m4 maths for helping to get placed in several companies.
I must recommend this website for placement preparations.