InterviewSolution
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InterviewSolution
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Let `(a_(1),b_(1))` and `(a_(2),b_(2))` are the pair of real numbers such that 10,a,b,ab constitute an arithmetic progression. Then, the value of `((2a_(1)a_(2)+b_(1)b_(2))/(10))` is |
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Answer» Let `a=10+D " " "……(i)"` `b=10+2D" " "…..(ii)"` `ab=10+3D" " "…….(iii)"` On substituting the values of a and b in Eq. (iii), we get `(10+D)(10+2D)=(10+3D)` `implies 2D^(2)+27D+90=0` `:.d=-6,D=-(15)/(2)` `:.a_(1)=10-6=4,a_(2)=10-(15)/(2)=(5)/(2)` and `b_(1)=10-12=-2, b_(2)=10-15=-5` Now, `((2a_(1)a_(2)+b_(1)b_(2))/(10))=((2xx10+10)/(10))=3`. |
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