
#1
Jun908, 10:08 PM

P: 83

Solve:
lim x>0 (tan 3(x+h)tan(3x))/h i hv no clue where to start =( 



#2
Jun908, 10:14 PM

P: 1,295

err.. tan (3h)/h?
simply plugging in 0 for x.. edit: are you sure x is approaching 0? initially, I thought it's h.. then the answer would have been 3+3tan(3x)^2 and you had to do some mess with identites.. http://www.clarku.edu/~djoyce/trig/identities.html 



#3
Jun908, 10:16 PM

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P: 25,174

Did you mean lim h>0??




#4
Jun908, 10:17 PM

P: 83

Limits problem 



#5
Jun908, 10:26 PM

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P: 25,174

Look up a formula for tan(A+B) and apply it to tan(3x+3h). Then simplify, take your limit and use some trig.




#6
Jun908, 10:41 PM

P: 1,295

It is actually very simple.. don't even need to any trig after simplifying tan(3x+3h) ..
should factor out things.. and they would cancel out nicely. And, one more thing tan(x)/x = 1 .. (which is simple to prove is you know sin(x)/x =1 as x>0) 



#7
Jun908, 10:45 PM

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P: 25,174





#8
Jun1008, 12:58 AM

P: 83

kk thanks i got it =)



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