trignometric functions (1 Viewer)

[xeriphic]

can someone help me with this question

1) a circular piece of wire has a radius of 12 cm. This is cut and bent to form an arc of a circle whose radius is 60 cm. Find the angle subtended at the centre by this arc. Give your answer to the nearest degree

thanks

 

[George W. Bush]

Your arc length is 12.
The radius of your circle is 60.
Therefore your angle is 0.2 radians
Convert to degrees.

 

[nike33]

just use the standard l=@r ...also note the angle will be minimally smaller than the one you find!

george..i may be misinterpriting this but l = 24pi

 

[George W. Bush]

oh yes, sorry.

 

[xeriphic]

i see, thanks for the help, couldn't relate those two piece of information together

also can someone help me with this

2) draw the curve of y = sin (x+pi/2)

i'm not sure when the curve begins, is it at x = -pi/2

 

[CM_Tutor]

The curve is continuous and has a domain of all real x, so it doesn't start anywhere.

However, it is identical to the curve y = cos x

It should be sketched as a continuous funtion (ie arrows on the 'ends', etc) unless you are asked to sketch it over a stated domain, in which case you should sketch it over that domain, with pen or closed circles at the ends (depending on the question).

 

[xeriphic]

if it doesn't provide a domain, do i just start at x = 0 and sketch

 

[CM_Tutor]

I'd probably sketch 0 to 2 * pi, then extend a little beyond each and put arrows on each end of the curve.

 

[xeriphic]

i see, thanks for the advice