NIMCET 2015 Question Paper with solutions

Question : 13 of 120

Marks: +1, -0

If A + B + C = π , then the value of

|\table sin(A+B+C),sinB,sinC;-sinB,0,tanA;cos (A + B) , -tanA , 0|

is :

Solution:

|\table \sin(A+B+C),\sin B,\sin C;-\sin B,0,\tan A;\cos (A + B) , -\tan A , 0|

⇒A=|\table \sin π,\sin B,\cos C;-\sin B,0,\tan A;\cos(π-c),\tan A,0|

[∵A+B+C=π]

⇒A=|\table 0,\sin B,\cos c;-\sin B,0,\tan A;-\cos C,\tan A,0|

A=0

[∵ A is skew-symmetrix C]
|A| = 0 matrix

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