## hothand621 2 years ago (sinA+cosAtanB)/(cosA-sinAtanB)=tan(a+b)

1. AravindG

Multiply with cos B on numerator and denominator.

2. hothand621

explain?

3. AravindG

you will se that you get something similar to previous question

4. AravindG

(sinA+cosAtanB) X cos B ________________________ (cosA-sinAtanB) X cos B

5. AravindG

Try opening up the brackets .

6. hothand621

ok, so you get this: $(sinAcosB+cosAcosBtanB)/(cosAcosB-sinAcosBtanB)$ so what next?

7. AravindG

tan B X cos B = ?

8. hothand621

?

9. AravindG

$\tan B \times \cos B= .....$ Can you find that ?

10. AravindG

@hothand621 ?

11. hothand621

ummmm no, i suck at harder trig

12. RolyPoly

Hint: tan B = sinB / cosB

13. AravindG

^^

14. hothand621

yes and that doesnt equal tan(a+b)

15. hothand621

it equals sinB

16. RolyPoly

Simplify it first :) No need to be hurry :)

17. AravindG

yep replace it in your question

18. hothand621

replace what though

19. AravindG

(sinA+cosAtanB) X cos B = sin A cos B+cos A sin B !

20. AravindG

Seen that somewhere?

21. hothand621

yes

22. AravindG

Can you do it now ?

23. hothand621

ummm give me a minute

24. hothand621

i think so

25. hothand621

what happens to the denominator?

26. AravindG

Open up the brackets !

27. AravindG

(cosA-sinAtanB) X cos B=.........

28. hothand621

thanks man, solved :)

29. AravindG

Great ! yw :)