19/11/2015
কিছু প্রয়োজনীয় সুত্রঃ
1. (a+b)²= a²+2ab+b²
2. (a+b)²= (a-b)²+4ab
3. (a-b)²= a²-2ab+b²
4. (a-b)²= (a+b)²-4ab
5. a² + b²= (a+b)²-2ab.
6.a² + b²= (a-b)²+2ab.
7. a²-b²= (a +b)(a -b)
8. 2(a²+b²)= (a+b)²+(a-b)²
9. 4ab = (a+b)²-(a-b)²
10. ab = {(a+b)/2}²-{(a-b)/2}²
11. (a+b+c)² = a²+b²+c²+2(ab+bc+ca)
12. (a+b)³ = a³+3a²b+3ab²+b³
13. (a+b)³ = a³+b³+3ab(a+b)
14. a-b)³= a³-3a²b+3ab²- b³
15.(a-b)³= a³-b³-3ab(a-b)
16. a³+b³= (a+b) (a²-ab+b²)
17. a³+b³= (a+b)³-3ab(a+b)
18. a³-b³ = (a-b) (a²+ab+b²)
19. a³-b³ = (a-b)³+3ab(a-b)
