C2 - Sine & Cosine Help
So basically, I'm not sure exactly what I'm doing wrong here.
Here's the question:
And here's what I've done (sorry its sideways):
Basically, as you can see, I got 5.35cm, but the answer says its 9.71cm, which makes more sense looking at the diagram. Can anyone tell me where I'm going wrong please?
Here's the question:
And here's what I've done (sorry its sideways):
Basically, as you can see, I got 5.35cm, but the answer says its 9.71cm, which makes more sense looking at the diagram. Can anyone tell me where I'm going wrong please?
Cos150 is a negative number.
So you are subtracting a negative number.
So instead you add.
Original post by L'Evil Fish
Cos150 is a negative number.
So you are subtracting a negative number.
So instead you add.
Cos150 is a negative number.
So you are subtracting a negative number.
So instead you add.
Oh I right. I just realised my calculator was set on radians, so that Cos150 = 0.69925.., so a positive number. Thank you
Original post by mynameisntbobk
Oh I right. I just realised my calculator was set on radians, so that Cos150 = 0.69925.., so a positive number. Thank you
I thought it would be, my phone is in radians -.- so I have to do:
Pi/180 * x
Where x is number of degrees
Original post by L'Evil Fish
I thought it would be, my phone is in radians -.- so I have to do:
Pi/180 * x
Where x is number of degrees
Pi/180 * x
Where x is number of degrees
Radians just make maths so much more longer
although more fun! Haha. Yeah, quite obvious to assume that the last work I was doing was radians
Why is your phone calculator in radians?
Original post by mynameisntbobk
Radians just make maths so much more longer although more fun!
Haha. Yeah, quite obvious to assume that the last work I was doing was radians
Why is your phone calculator in radians?
although more fun! Haha. Yeah, quite obvious to assume that the last work I was doing was radians
Why is your phone calculator in radians?
It is nice when you get an exact number in radians
No idea, it's stuck like that
Original post by L'Evil Fish
It is nice when you get an exact number in radians
No idea, it's stuck like that
No idea, it's stuck like that
It really is. Although converting one another is a pain because I always forget which one to multiply by pi/180 and 180/pi
Ah, reset your phone to factory settings?
Original post by mynameisntbobk
Radians just make maths so much more longer although more fun!
Haha. Yeah, quite obvious to assume that the last work I was doing was radians
Why is your phone calculator in radians?
although more fun! Haha. Yeah, quite obvious to assume that the last work I was doing was radians
Why is your phone calculator in radians?
Wait till you get onto differentiation then you'll know why you should use radians in real life because if you use degrees then you have to convert the function into radians, differentiate and then back into degrees.
Original post by Dalek1099
Wait till you get onto differentiation then you'll know why you should use radians in real life because if you use degrees then you have to convert the function into radians, differentiate and then back into degrees.
I thought you use radians because its general application to circles, or is that too basic an explanation?
Original post by mynameisntbobk
It really is. Although converting one another is a pain because I always forget which one to multiply by pi/180 and 180/pi
Ah, reset your phone to factory settings?
Ah, reset your phone to factory settings?
I just remember... 2Pi = 360 and pi/2 = 90...
It is the factory setting...
And we use radians in trig ^
Original post by mynameisntbobk
I thought you use radians because its general application to circles, or is that too basic an explanation?
That is another application because using radians simplifies things up like the length of an arc is (theta/360)*2*pi*r for degrees or just theta*radius for radians.By the way the gradient of sin(x radians) is cos(x radians) and the gradient of sin(x degrees) is (pi/180)cos(x degrees), which tells me that pi is supposed to be involved in angles.
(edited 11 years ago)
Original post by L'Evil Fish
I just remember... 2Pi = 360 and pi/2 = 90...
It is the factory setting...
And we use radians in trig ^
It is the factory setting...
And we use radians in trig ^
Yeah, that would confuse me
Oh wow, well I know I won't yet your phone.
Do you actually? Sounds horrid
Original post by Dalek1099
That is another application because using radians simplifies things up like the length of an arc is (theta/360)*2*pi*r for degrees or just theta*radius for radians.By the way the gradient of sin(x radians) is cos(x radians) and the gradient of sin(x degrees) is (pi/180)cos(x degrees), which tells me that pi is supposed to be involved in angles.
Ah yeah, that is true. But its always a struggle adapting to radians if you've spent your whole maths career using degrees.
Can I also ask with this question:
Is this diagram correct?
Is this diagram correct?
Original post by mynameisntbobk
Can I also ask with this question:
Is this diagram correct?
Is this diagram correct?
Hmm, I don't think so. I haven't done this kind of thing in a while, but I believe it should be something like this:
Spoiler
(edited 11 years ago)
Original post by L'Evil Fish
I just remember... 2Pi = 360 and pi/2 = 90...
It is the factory setting...
And we use radians in trig ^
It is the factory setting...
And we use radians in trig ^
What phone do u use?
Original post by baggyyo
What phone do u use?
Sony Ericsson Xperia Arc S
Original post by L'Evil Fish
Sony Ericsson Xperia Arc S
Ah okay because my phone was like that and then I changed it so I thought I could help but it's not your phone.
Original post by baggyyo
Ah okay because my phone was like that and then I changed it so I thought I could help but it's not your phone.
ah, doesn't make a difference
radians are usefulOriginal post by justinawe
Hmm, I don't think so. I haven't done this kind of thing in a while, but I believe it should be something like this:
Spoiler
Yeah, I realised yesterday I drew it wrong and then got the answer, but thank you
Original post by L'Evil Fish
ah, doesn't make a difference radians are useful
radians are usefulIt's convenient to be able to switch though.
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