1/(5-2 square root 8) - 1/(5+2square root 8)=??
Does some one can help me this question!?
OA is -4 square root 8/7
Does some one can help me this question!?
OA is -4 square root 8/7
Solution:
1/[5 - 2*sqrt(8)] = (5+2*sqrt(8))/[(5 - 2*sqrt(8))*(5 + 2*sqrt(8)] = (5+2*sqrt(8))/(25 - 32) = -(5+2*sqrt(8))/7. (multiplying both numerator and denominator by (5+2*sqrt(8))
Also 1/(5+2*square root 8) = (5 - 2*sqrt(8))/[(5 - 2*sqrt(8))*(5 + 2*sqrt(8)] =
(5 - 2*sqrt(8))/(25 - 32) = -(5- 2*sqrt(8))/7. (multiplying both numerator and denominator by (5 - 2*sqrt(8))
So 1/[5 - 2*sqrt(8)] - 1/(5+2*square root 8) = -(5+2*sqrt(8))/7 + (5- 2*sqrt(8))/7 = -(4*sqrt(8))/7.
