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
Use suitable identity to find the following product:
(3x + 4) (3x – 5)
Evaluate the following using identities:
117 x 83
Simplify `(x^2 + y^2 - z)^2 - (x^2 - y^2 + z^2)^2`
If \[x + \frac{1}{x} = 5\], find the value of \[x^3 + \frac{1}{x^3}\]
Evaluate of the following:
(99)3
Simplify of the following:
If a + b + c = 9 and ab + bc + ca = 23, then a2 + b2 + c2 =
Evalute : `( 7/8x + 4/5y)^2`
Use the direct method to evaluate the following products :
(y + 5)(y – 3)
Use the direct method to evaluate :
(0.5−2a) (0.5+2a)
