if x=11-2√30 then find (a)√x+1/√x (b) √x-1/√x
Answers
Answer:
a) √x + 1/ √x =2 √6
b) √x - 1/ √x = -2√5
Step-by-step explanation:
Given---> x=11 - 2√30
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To find--->
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a) √x + 1/√x
b) √x - 1/√x
Solution--->
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We have
x = 11 -2√30
=6 + 5 - 2√(6 × 5)
=(√6)² + ( √5)² - 2 √6 √5
=> x =( √6 - √5 )²
Now
√x = √(√6 - √5)²
= √6 - √5
1/√x = 1/(√6 - √5)
Multiplying by (√6 +√ 5) in numreator and denominator
1/√x = (√6+√5) / (√6 - √5) (√ 6 + √5 )
=(√6 + √5 ) / ( √6)² - ( √5)²
=(√6 + √ 5 ) /( 6 - 5)
= (√6 + √5) /1
= √6 + √ 5
Now
a) √x + 1/√x = (√6 - √ 5) + (√6 + √5)
+√ 5 and - √5 cancel out each other
√x + 1/√x = 2√6
b) √x - 1/ √x =(√6 - √ 5) - (√ 6 + √5)
= √6 - √5 - √6 - √5
+√6 and -√6 cancel out each other
√x - 1/√x =-2 √5
Answer:
X2=11+2√ 30
X=√ (11+√ 30)
X=√ ((√ 6)2+ (√ 5)2+ (2×√ 6×√ 5))
X=√6+√5