Question

If a+1/a= 17/4,then the value of (a - 1/a) is:-​

Answer 1

Answer :

Given (a+1/a) 2 = 3

Therefore (a + 1/a) = √3

Recall the formula, (a3 + b3) = (a + b)3 - 3ab(a + b)

Therefore, (a3 + 1/a3) = (a + 1/a)3 - 3 x a x 1/a (a + 1/a)

                                =  (√3)3 - 3(√3) = 3√3 - 3(√3 = 0

Answer 2

Answer:

a+1/a=17/4

(a^2+1)/a=17/4

4a^2+4=17a

4a^2-17a+4=0

4a^2-(16a+1a)+4=0

4a^2-16a-1a+4=0

4a(a-4)-1(a-4)=0

(a-4)(4a-1)

a=4 and a=1/4

then (a-1/a)

(4-1/4)=15/4

15/4 ans

when put a=1/4 then

(1/4-1/1/4)

(1/4-4)

-15/4 ans