Advertisements
Advertisements
प्रश्न
If a2 - 3a - 1 = 0 and a ≠ 0, find : `"a" + (1)/"a"`
Advertisements
उत्तर
`"a" - (1)/"a"` = 3
Squaring both sides, we get
`("a" - 1/"a")^2`
= `"a"^2 + (1)/"a"^2 - 2`
= 9
⇒ `"a"^2 + (1)/"a"^2`
= 11.
Now,
`("a" + 1/"a")^2`
= `"a"^2 + (1)/"a"^2`
= 11 + 2
= 13
⇒ `"a" + (1)/"a"^2`
= ±`sqrt(13)`.
APPEARS IN
संबंधित प्रश्न
Evaluate the following using suitable identity:
(102)3
Factorise the following:
`27p^3-1/216-9/2p^2+1/4p`
Find the following product:
Use the direct method to evaluate :
(3x2+5y2) (3x2−5y2)
Use the direct method to evaluate :
(0.5−2a) (0.5+2a)
Evaluate: `(3"x"+1/2)(2"x"+1/3)`
Evaluate: (2a + 0.5) (7a − 0.3)
If `"a" + (1)/"a" = 2`, then show that `"a"^2 + (1)/"a"^2 = "a"^3 + (1)/"a"^3 = "a"^4 + (1)/"a"^4`
Find the value of x3 – 8y3 – 36xy – 216, when x = 2y + 6
Prove that (a + b + c)3 – a3 – b3 – c3 = 3(a + b)(b + c)(c + a).
