If a cos A = b cos B,then Delta ABC is | vedclass

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(D) Given $a \cos A = b \cos B$. Using the sine rule,$a = 2R \sin A$ and $b = 2R \sin B$. Substituting these,we get $2R \sin A \cos A = 2R \sin B \cos

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right angled or isosceles

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(D) Given $a \cos A = b \cos B$. Using the sine rule,$a = 2R \sin A$ and $b = 2R \sin B$. Substituting these,we get $2R \sin A \cos A = 2R \sin B \cos B$. $\Rightarrow \sin 2A = \sin 2B$. This implies $2A = 2B$ or $2A = \pi - 2B$. $\Rightarrow A = B$ or $A + B = \frac{\pi}{2}$. If $A = B$,the triangle is isosceles. If $A + B = \frac{\pi}{2}$,then $C = \pi - (A + B) = \frac{\pi}{2}$,so the triangle is right-angled. Therefore,the triangle is right-angled or isosceles.

If $a \cos A = b \cos B$,then $\Delta ABC$ is

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