- #1

chukie

- 80

- 0

Solve:

lim x->0 (tan 3(x+h)-tan(3x))/h

i hv no clue where to start =(

lim x->0 (tan 3(x+h)-tan(3x))/h

i hv no clue where to start =(

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- Thread starter chukie
- Start date

- #1

chukie

- 80

- 0

Solve:

lim x->0 (tan 3(x+h)-tan(3x))/h

i hv no clue where to start =(

lim x->0 (tan 3(x+h)-tan(3x))/h

i hv no clue where to start =(

- #2

rootX

- 465

- 4

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

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

Last edited:

- #3

Dick

Science Advisor

Homework Helper

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Did you mean lim h->0??

- #4

chukie

- 80

- 0

Did you mean lim h->0??

sry, yes i mean lim h->0

- #5

Dick

Science Advisor

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- #6

rootX

- 465

- 4

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

Dick

Science Advisor

Homework Helper

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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)

Yep. You don't have to use any trig. But using sec^2(A)=1+tan^2(A) would put it in the simpler form listed in books.

- #8

chukie

- 80

- 0

kk thanks i got it =)

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