Question

let f(x)=sin(lnx)

a.find two values of x satisfying f(x)=1
b.find two values of x satisfying f(x)=-1

Answer 1

What is the ln(1) and ln(-1)?

Answer 2

I don't know

Answer 3

Do you have a calculator?

Answer 4

yes

Answer 5

OK ln references "natural log" you should have an ln button on your calculator. Push ln and enter 1. What do you get?

Answer 6

@nelsonjedi I got 0

Answer 7

So the sine(0) = ?

Answer 8

0

Answer 9

Right . Did you try ln(-1) ?

Answer 10

yeah it said nonreal answer

Answer 11

I did this all wrong..Let me take a look as I misread the question..Sorry

Answer 12

ok

Answer 13

f(x) =1 therefore 1 = sine (lnx). The arcsine of 1 = 1.507 thus 1.507 = (lnx).(this removes the sine) Expotiniate both sides by e (to remove the ln) and we get 1.507^e = x or 4.513 = x. You would do the same for -1.

Answer 14

I see you required to have two answers so you would have to add 2pi to 1.507 for your second answer or 7.790 and solve as I did above. Does this help?

Answer 15

yes it does, thanks!

Answer 16

You are welcome. :-}