Advertisements
Advertisements
Question
if `x^2 + 1/x^2 = 79` Find the value of `x + 1/x`
Advertisements
Solution
We have
`(x + 1/x)^2 = x^2 + 1/x^2 + 2 xx x xx 1/x`
`=> (x + 1/x)^2 = (x^2 + 1/x^2) + 2`
`=> (x + 1/x)^2 = 79 + 2`
`=> (x + 1/x)^2 = 81`
`=> (x + 1/x)^2 = (+-9)^2`
`=> x + 1/x = +-9`
APPEARS IN
RELATED QUESTIONS
Write in the expanded form (a2 + b2 + c2 )2
Write in the expanded form: (ab + bc + ca)2
Simplify (a + b + c)2 + (a - b + c)2
Find the value of 4x2 + y2 + 25z2 + 4xy − 10yz − 20zx when x = 4, y = 3 and z = 2.
If x = −2 and y = 1, by using an identity find the value of the following
If \[x + \frac{1}{x} = 2\], then \[x^3 + \frac{1}{x^3} =\]
(a − b)3 + (b − c)3 + (c − a)3 =
Find the square of : 3a - 4b
Evalute : `((2x)/7 - (7y)/4)^2`
Use the direct method to evaluate the following products:
(5a + 16) (3a – 7)
Use the direct method to evaluate :
`("z"-2/3)("z"+2/3)`
If p2 + q2 + r2 = 82 and pq + qr + pr = 18; find p + q + r.
If x + y + z = p and xy + yz + zx = q; find x2 + y2 + z2.
If `"r" - (1)/"r" = 4`; find: `"r"^2 + (1)/"r"^2`
If `"r" - (1)/"r" = 4`; find : `"r"^4 + (1)/"r"^4`
Simplify:
(3a - 7b + 3)(3a - 7b + 5)
Expand the following:
(4a – b + 2c)2
Expand the following:
(–x + 2y – 3z)2
If a + b + c = 5 and ab + bc + ca = 10, then prove that a3 + b3 + c3 – 3abc = – 25.
Prove that (a + b + c)3 – a3 – b3 – c3 = 3(a + b)(b + c)(c + a).
