Advertisements
Advertisements
Question
If `"r" - (1)/"r" = 4`; find : `"r"^3 - (1)/"r"^3`
Sum
Advertisements
Solution
`("r" - 1/"r")^3`
=`"r"^3 - (1)/"r"^3 - 3("r" - 1/"r")`
⇒ (4)3 = `"r"^3 - 1/"r"^3 - 3(4)`
⇒ `"r"^3 - (1)/"r"^3`
= 64 + 12
= 76.
shaalaa.com
Is there an error in this question or solution?
APPEARS IN
RELATED QUESTIONS
Find the cube of : 5a + 3b
If a2 + `1/a^2 = 47` and a ≠ 0 find :
- `a + 1/a`
- `a^3 + 1/a^3`
If a ≠ 0 and `a - 1/a` = 3 ; find `a^2 + 1/a^2`
Find the cube of: 4x + 7y
Find the cube of: `3"a" + (1)/(3"a")`
Find the cube of: `4"p" - (1)/"p"`
Find the cube of: `"a" - (1)/"a" + "b"`
If `x^2 + (1)/x^2 = 18`; find : `x^3 - (1)/x^3`
If a + 2b + c = 0; then show that a3 + 8b3 + c3 = 6abc
Expand (3 + m)3
