## ashna 3 years ago If tan A - tan B = x and cot B - cot A =Y , pt COT (a-b) = 1/X + 1/Y

1. ashna

@akash123

2. akash123

sin(A-B)/ cosA*cosB =1/x from Tan A - tan B=x

3. ashna

okay !

4. ashna

then ?

5. akash123

and sin(A-B)/ sinA* SinB=y from cotB- cotA =y sin(A-B)/ cosA*cosB =x from Tan A - tan B=x tanA*tanB= x/y

6. sauravshakya

@akash123 sin(A-B)/ cosA*cosB =x from Tan A - tan B=x

7. akash123

cot(A-B) = [ cot A* cot B+1] / ( cot B - cot A)

8. akash123

yes...thanks...I have corrected it later

9. akash123

sin(A-B)/ sinA* SinB=y from cotB- cotA =y sin(A-B)/ cosA*cosB =x from Tan A - tan B=x divide 2nd by 1st then u'll get tanA*tanB= x/y

10. ashna

yes i understood that !

11. akash123

now use the identity cot(A-B) = [ cot A* cot B+1] / ( cot B - cot A) and substitute the value of cot A* cot B and (cot B- cot A) then u'll get the answer

12. akash123

another way @sauravshakya write the reciprocal f 1st and 2nd equation and add both then simplify it.

13. sauravshakya

Yep... I would go with that....

14. ashna

okay got it :) thank you !

15. akash123

:)