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If cosB = (sinA)/(2sinC) prove that the ...

If cosB = (sinA)/(2sinC) prove that the triangle is isosceles.

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If cosB = (sinA)/(2sinC)
`rArr (c^2+ a^2-b^2)/(2ca) = a/92c) rArr c^2 + a^2 - b^2 = a^2`
or,` c^2 = b^2 pr c = b`
`therefore` the triangle is isosceles.
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MBD PUBLICATION-TRIGONOMETRIC FUNCTIONS-QUESTION BANK
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  13. If cosB = (sinA)/(2sinC) prove that the triangle is isosceles.

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  14. If a tan A + b tanB = (a+b) tan ((A+B)/2) prove that the triangle is i...

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  15. If (cosA + 2cosC) : (cosA + 2cosB) = sinB : sinC prove that the tria...

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  16. If cos A = sinB - cosC prove triangle is right angled.

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  17. If a^2,b^2,c^2 being A.P prove that cotA,cotB,cotC are also In A.P.

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  18. If sinA : sinC = sin(A-B): sin(B-C) prove that a^2,b^2,c^2 are in A.P.

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