Advertisements
Advertisements
Question
Find : `"a"^3+1/"a"^3`, if `"a" +1/"a"=5`.
Sum
Advertisements
Solution
`"a" +1/"a"=5`
`⇒("a"+1/"a")^3=(5)^3`
`⇒"a"^3+1/"a"^3+3"a"xx1/"a"("a"+1/"a")=125`
`⇒"a"^3+1/"a"^3+3(5)=125` ........`["a"+1/"a"=5]`
`⇒"a"^3+1/"a"^3+15=125`
`⇒"a"^3+1/"a"^3=125-15`
`⇒"a"^3+1/"a"^3=110`
shaalaa.com
Application of Formulae
Is there an error in this question or solution?
APPEARS IN
RELATED QUESTIONS
If a – b = 6 and ab = 16, find a2 + b2
If a2 + b2= 10 and ab = 3; find : a – b
If `"a"^2+ 1/"a"^2=23`, find : `"a" +1/"a"`
Find: a2 + b2 + c2, if a + b + c = 9 and ab + bc + ca = 24
Find : a + b + c, if a2 + b2 + c2 = 83 and ab + bc + ca = 71.
If `2"x"-1/(2"x")=4`, find : `4"x"^2+1/(4"x"^2)`
If 3x – 4y = 5 and xy = 3, find : 27x3 – 64y3.
If a + b = 8 and ab = 15, find a3 + b3.
If 3x + 2y = 9 and xy = 3, find : 27x3 + 8y3.
If 5x – 4y = 7 and xy = 8, find : 125x3 – 64y3.
