KeerthanaPosted on If N=(6−5)(6+5)mathrm{N}=frac{(sqrt{6}-sqrt{5})}{(sqrt{6}+sqrt{5})}N=(6+5)(6−5), then what is the value of N+mathrm{N}+N+ (1N)?left(frac{1}{N} ight) ?(N1)? a10 b11 c12 d22 Answer : Option DExplanation : N=6−56+5=6−56+5×6−56−5mathrm{N}=frac{sqrt{6}-sqrt{5}}{sqrt{6}+sqrt{5}}=frac{sqrt{6}-sqrt{5}}{sqrt{6}+sqrt{5}} imes frac{sqrt{6}-sqrt{5}}{sqrt{6}-sqrt{5}}N=6+56−5=6+56−5×6−56−5 =(6−5)2(6)2−(5)2=6+5−2306−5=frac{(sqrt{6}-sqrt{5})^{2}}{(sqrt{6})^{2}-(sqrt{5})^{2}}=frac{6+5-2 sqrt{30}}{6-5}=(6)2−(5)2(6−5)2=6−56+5−230 =11−230=11-2 sqrt{30}=11−230 ∴1 N=11+230 herefore frac{1}{mathrm{~N}}=11+2 sqrt{30}∴ N1=11+230 ∴N+1 N=11−230+11+230=22 herefore mathrm{N}+frac{1}{mathrm{~N}}=11-2 sqrt{30}+11+2 sqrt{30}=22∴N+ N1=11−230+11+230=22 Rate This:NaN / 5 - 1 votesAdd comment