Question

Using complete sentences, explain how to find the y-intercept for each function and determine which function has the largest y-intercept.

f(x) = 2 tan(3x + π)

g(x) = 3 sin(4x - π) - 2

I have absolutely no idea how to solve for this without just graphing the equations, and I am pretty sure that I have to explain how to find the y-intercepts without graphing them. I have tried solving for "x = 0", but I didn't get the correct values for the y-intercepts (I graphed these equations to check).

Answer 1

you plug in 0 for x to get the y-intercepts.
f(x) = 2 tan (3x + π)
f(0) = 2 tan (π)
f(0) = 0
y-intercept (0, 0)

Answer 2

Wouldn't it be
f(0) = 2 tan( (3*0) + π )
f(0) = 2 tan(0 + π)
f(0) = 2 tan(π)

Answer 3

yes I just skipped those steps

Answer 4

Oh, I see.
So then:
f(0) = 2 tan(π)
f(0) = 2 (0.0548861508)
f(0) = 0.1097723016

This isn't exactly 0 :( This is where I keep struggling :/

Answer 5

And on the graph, it doesn't display as "0.10977..". It says (0, 0). :((

Answer 6

your calculator is in degree mode. change it to radian :)

Answer 7

OHHHHHHHHHHHHHHHHHHHHHHHHH

Answer 8

Thank you so much, omg. I would have never thought to do that. I don't even know how to, since I was using my phone. I'll use my computer calculator. So
tan(π) = 0 radians?

Answer 9

tan (π radians) = 0
radians is just another way to measure the angle. (π radians = 180°)

Answer 10

but yeah, just put tan π in the calc

Answer 11

It still gives me "0.0548861508" D:

Answer 12

http://www.wolframalpha.com/input/?i=tan+0

Answer 13

OOHHHHH http://www.wolframalpha.com/input/?i=tan+%CF%80

Answer 14

So my calculators were reading it as "3.141592..." and not as "pi radians", then. This makes things so much clearer now. I really appreciate all of your time and help.

Answer 15

no problem