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নবম-দশম শ্রেণির গণিতের বীজগণিত এবং ত্রিকোনোমিতির যাবতীয় সূত্রাবলি

, February 19, 2019 WAT
Last Updated 2019-10-26T21:25:43Z
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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(α² + в²) = (a + в)² + (a – в)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) a³ + b³ = (a + b) (a² – ab + b²)
16) a³ + b³ = (a + b)³ – 3ab (a + b)
17) a³ -b³ = (a – b) (a² + ab + b²)
(18) a³ – b³ = (a – b)³ + 3ab (a – b)

( 19) (a + b + c)² = a² + b² + c² + 2(ab + bc + ca)
  1. sin(A + B) = sinA.cosB + cisA.sinB
  2. sin(A - B) = sinA.cosB - cisA.sinB
  3. cos(A + B) = cosA.cosB - sinA.sinB
  4. cos(A - B) = cosA.cosB + sinA.sinB
  5. tan(A + B) = tanA + tanB1 - tanA.tanB
  6. tan(A - B) = tanA - tanB1 + tanA.tanB
  7. cot(A + B) = cotA.cotB - 1cotA + cotB
  8. cot(A - B) = cotA.cotB + 1cotB - cotA
  9. sin(A + B).sin(A - B) = sin2A - sin2B = cos2B - cos2A
cos(A + B).cos(A - B) = cos2A - sin2B = cos2B - sin2A