Question

cot A cot B =2 prove that cos ( A+ B) / cos ( A - B) = 1/3​

Answer 1

Step-by-step explanation:

cotA cotB = 2

cosA cosB= 2 SinA SinB

L.H.S = Cos(A+B) / Cos(A-B)

= (cosAcosB - sinAsinB)

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cosAcosB +sinAsinB

= sinAsinB/3sinAsinB

= 1/3 = R.H.S