#Zeros of the function y=sinx
thick geodeBOT
surreal herald
the zeroes of sin x are the x values for which sin x = 0, do you understand that bit?
smoky oak
If I'm not mistaken, the zeros of the function are where the lines touch the x-axis.
gloomy root
the zeroes of sin x are the x values for which sin x = 0, do you understand tha...
i dont understand anything
smoky oak
X=0+180? Idk
surreal herald
If I'm not mistaken, the zeros of the function are where the lines touch the x-a...
that is what i said, yes
gloomy root
that is what i said, yes
how do u know tthat tho
lavish dove
the zeroes of any function is when the value of the function is 0, and where would the graph of a function be if the function is 0?
that's the idea being communicated here.
gloomy root
okay yeah i undrstood thatbut im confused about th part where i have to turn 270 into radian
lavish dove
if your confusion is about converting radians to degrees and vice versa, do remember that 180 degrees = π radians, so you can scale this as necessary.
for example, say you want to find 45 degrees in radians. well, 45 degrees is 180/4 degrees, and 180 degrees is π radians, so 180/4 degrees must be π/4 radians.
smoky oak
Each of these "waves" is equal to 180°.
gloomy root
how do i do it to 130°
or like -200°
i ahve a test on this tomorrow and i dont understand anything
surreal herald
how do i do it to 130°
just use the fact that pi radians = 180 degrees
lavish dove
how do i do it to 130°
the same idea I mentioned applies to any angle.
gloomy root
lavish dove
and yeah, that's a good first step! now you will just have to simplify the fraction.
gloomy root
and yeah, that's a good first step! now you will just have to simplify the fract...
i don’t know howew
smoky oak
Hmm i think the zero of the function in the interval is Pi
lavish dove
can you simplify 130/180 without the pi?
lavish dove
Hmm i think the zero of the function in the interval is Pi
I think we're talking about another question now.
gloomy root
can you simplify 130/180 without the pi?
13/18
lavish dove
yes! so do the same to the fraction here. just because a pi is present doesn't mean the numbers are treated any differently.
gloomy root
it doesn’t need to be smaller?
lavish dove
what do you mean?
lavish dove
you can further simplify -20/18.
gloomy root
-2/9
lavish dove
incorrect.
gloomy root
-10/9
lavish dove
one look at it tells us that, because your numerator went from being larger than the denom to being smaller than the denom, which should not happen.
lavish dove
everything was fine, up till the second = sign in line 3 (the line starting with x =).
not sure what's happening in the numerator there. I see that you tried to multiply top and bottom by 2 to eliminate the two mini-fractions, but somehow that introduced a minus sign where there is none.
(btw, if I disappear halfway through this conversation, I apologize, as it's bedtime for me technically. please use the Helpers ping if necessary.)
lavish dove
so the sign between the sqrt(2) and 2 on the numerator of that fraction is a dot, not a minus?
it looked very suspiciously like a minus sign. moght want to take care of that.
gloomy root
so the sign between the sqrt(2) and 2 on the numerator of that fraction is a dot...
no its a minus
lavish dove
there should be no subtraction involved in multiplication and division.
if that is indeed a minus sign, then it's wrong, unfortunately.
if it was a multiplication dot, then it is correct.
for reference, $\frac{\frac{a}{b}}{\frac{c}{d}} = \frac{ad}{bc}$.
west thicketBOT
Hyacine
lavish dove
notice that there is no minus (or plus) sign introduced here.
gloomy root
why did my teacher show us that then
lavish dove
you may have miscopied the dot for a minus sign.
worth asking your teacher to clarify.
gloomy root
Okay but how do i square root 2 times 2
lavish dove
normally we just leave it as 2sqrt(2).
lavish dove
what's going on in the numerator?
never mind, I see what you did.
probably shouldn't have done that, because the 2 in the numerator can cancel against the 2 in the denominator.
after that, you can't proceed nornally any more. use your calculator to evaluate the expression.
gloomy root
lavish dove
after that, you can't proceed nornally any more. use your calculator to evaluate...
^
if no calculator is allowed, this will be your final answer.
gloomy root
we are allowed to have calculators
lavish dove
then do the step I highlighted for the actual answer. round it to a suitable number of digits (usually 3).
gloomy root
but in lessons we had to do this
lavish dove
oh you want to rationalize the debominator first. sure, multiply both top and bottom by the denominator then.
gloomy root
how
lavish dove
you've shown the steps needed already.
look at your own working, towards the end where you multiply both top and bottom by sqrt(2).
do the same in your problem here, but your denominator is not sqrt(2) here, so use your denominator.
gloomy root
idk how to do it
lavish dove
but you did it?
gloomy root
lavish dove
this part.
lavish dove
now, I did mention you are to multiply by the denom. your denom in that problem is not sqrt(2), but sqrt(3).
so you are to multiply both top and bottom by sqrt(3), not sqrt(2).
I'm curious, though, because I thought by telling you to just multiply top and bottom by the denominator, it was pretty clear.
gloomy root
I'm curious, though, because I thought by telling you to just multiply top and b...
english isnt my first language
lavish dove
merge it with the sqrt(2) to get sqrt(6).
gloomy root
sorry
lavish dove
english isnt my first language
ah, noted.
gloomy root
how
west thicketBOT
Hyacine
lavish dove
hopefully this is familiar to you. if not, please consider skimming through your radical laws.
anyway, you have simplified this as far as it goes after merging the two roots together, unless you want to divide the 36.6 against the 3 in the denominator.
after that it's just calculator bashing.
lavish dove
it's not 9 in the bottom.
lavish dove
why is there a sqrt(6) in the bottom then?
lavish dove
anyway, you have simplified this as far as it goes after merging the two roots t...
sure. then continue.
I've pretty much laid the rest of the steps all the way to the answer.
gloomy root
i don’t get it
lavish dove
what do you not get?
lavish dove
it's correct so far.
and if you're asked for the answer in this form, then you don't need a calculator.
but you will need to simplify the 36.6 in the top against the 3 in the bottom.
gloomy root
lavish dove
yes.
gloomy root
okay thank you
lavish dove
glad to help.
gloomy root
how do i know when to use sin theorem and cos
lavish dove
depends on the information you have and what you want to find.
gloomy root
how
lavish dove
one certain indication you want the law of sines is when you're given two sides and one of the corresponding angles and are asked to find the other one.
if you're given two sides, one angle, and are asked to find the last side, that would be a job for the law of cosines.
as for anything else, I don't know of any tips off the top of my head, unfortunately.
surreal herald
what are you trying to say
gloomy root
like when do u use cos and when sin theorem
because in both u need to calculate a side
surreal herald
like when do u use cos and when sin theorem
cosine theorem: if you have an included angle and know the two sides including it, it's a big hint to use the cosine rule
sine theorem: when you have one side and one angle opposite that side, another big hint to use sine rule
lavish dove
maybe I should rephrase my sine law part. if you're given two sides, one corresponding angle, and are asked to find the other corresponding angle, then sine law it is.
surreal herald
there are no hard and fast rules to when to apply these theorems, use them where you see fit.
lavish dove
there are situations where either theorem may work as long as you apply them right.