यदि \(a=1+\sqrt{5}\), तो \(a^2-2a\) का मान क्या है?
If \(a=1+\sqrt{5}\), what is the value of \(a^2-2a\)?
Explanation opens after your attempt
Correct Answer
A. (4)
Concept
(a-2-2a=a(a-2)).
Why this answer is correct
\(a-2=\sqrt{5}-1\), so (a(a-2)=\(1+\sqrt{5}\)\(\sqrt{5}-1\)=4).
Exam Tip
Recognizing the hidden conjugate form is a quick method. चरण 1: (a-2-2a=a(a-2)) है। चरण 2: \(a-2=\sqrt{5}-1\), इसलिए (a(a-2)=\(1+\sqrt{5}\)\(\sqrt{5}-1\)=4)। चरण 3: छिपे हुए संयुग्मी रूप को पहचानना तेज तरीका है।
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