if A and b are acute angles such that cosA=cosB, then show that ANGLEA=ANGLEB.

Take a right angled triangle ABC roght angled at C ;

Here, cos A = AC/AB

cos B = BC/AB

Given cos A = Cos B;

AC/AB = BC/AB

So A = B

if A and b are acute angles such that cosA=cosB, then show that ANGLEA=ANGLEB.

Take a right angled triangle ABC roght angled at C ;

Here, cos A = AC/AB

cos B = BC/AB

Given cos A = Cos B;

AC/AB = BC/AB

So A = B

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