Advertisements
Advertisements
प्रश्न
If a + b + c = 11 and a2 + b2 + c2 = 81, find : ab + bc + ca.
योग
Advertisements
उत्तर
Since (a + b + c)2 = a2 + b2 + c2 + 2 (ab + bc + ca)
∴ (11)2 = 81 + 2 (ab + bc + ca)
∴ 2(ab + bc + ca) = 121 − 81 = 40
ab + bc + ca = `40/2`
⇒ ab + bc + ca = 20
shaalaa.com
Application of Formulae
क्या इस प्रश्न या उत्तर में कोई त्रुटि है?
APPEARS IN
संबंधित प्रश्न
If a2 + b2 = 29 and ab = 10, find : a − b
If a2 + b2= 10 and ab = 3; find : a + b
If `"a" - 1/"a"=4`, find : `"a"^2+1/"a"^2`
If `"a"^2+ 1/"a"^2=23`, find : `"a" +1/"a"`
If `"a"^2+ 1/"a"^2=11`, find : `"a" -1/"a"`
Find : a + b + c, if a2 + b2 + c2 = 83 and ab + bc + ca = 71.
Find : `"a"^3+1/"a"^3`, if `"a" +1/"a"=5`.
If `2"x"-1/(2"x")=4`, find: `8"x"^3-1/(8"x"^3)`
If a2 + b2 = 41 and ab = 4, find : a – b
If a + b + c = 9 and ab + bc + ca = 15, find: a2 + b2 + c2.
