Trig Functions (1 Viewer)

[sannous1]

hey im currently doin trig functions, and im really confused about when to use pie on ur calculator or let pi = 180,

can any1 help me please?

 

[tommykins]

what?

 

[Timothy.Siu]

hey im currently doin trig functions, and im really confused about when to use pie on ur calculator or let pi = 180,

can any1 help me please?

never use pie but u can use pi if its in radian mode.

 

[T7]

i think you mean when do we use degree and when do we use radian?

generally, for most questions that we do now, it is in radian
for example in the topic of calculus

sorry, your question needs to be more specific for us to help

 

[addikaye03]

If you have anything to do with differentating trig functions then always use radians. Some formulas require radians: A=1/2r^2@ etc. Umm.. if a Q has a restriction or alludes to radians e.g 0<@<pi

 

[Timothy.Siu]

think they're asking for calculator work, basically u use pi (radians) if the calculator is in radian mode, otherwise u can always just use degrees just make sure u convert radians to degrees if the values were originally radians

 

[studentcheese]

You use radians in trigonometry when the question is in radians too. If not, then don't bother. If you find that using radians is a bit of a bother, then convert them to degrees, work the answer out and then convert back to radians.

You set your calculator to RAD mode when you work with trigonometric equations with radians in them. If you have your calculator in DEG mode, then you will get an entirely different answer.

Is that what you were asking?

 

[tommykins]

You use radians in trigonometry when the question is in radians too. If not, then don't bother. If you find that using radians is a bit of a bother, then convert them to degrees, work the answer out and then convert back to radians.

You set your calculator to RAD mode when you work with trigonometric equations with radians in them. If you have your calculator in DEG mode, then you will get an entirely different answer.

Is that what you were asking?

get used to using radians maeng.

 

[sannous1]

OK for eg

1) find the area of the minor segment if radius is 1.5m and the angle subtended is 0.43

2) find the area of the minor segment if radius is 7.2mm and the angle subtended is 55 degrees.

3) find the area of the minor segment if radius is 2.1 m and the angle subtended is 82° 35'

4) find the area of the minor segment if radius is 3cm and angle is subtended at π/7

 

[tommykins]

use radians

 

[Drongoski]

OK for eg

1) find the area of the minor segment if radius is 1.5m and the angle subtended is 0.43

2) find the area of the minor segment if radius is 7.2mm and the angle subtended is 55 degrees.

3) find the area of the minor segment if radius is 2.1 m and the angle subtended is 82° 35'

4) find the area of the minor segment if radius is 3cm and angle is subtended at π/7

Salaam'ulaikum !

Area of segment = area of sector - area of triangle
= 0.5 x r^2 x @ - 0.5 x r^2 x sin @
= 0.5 x r^2 x (@ - sin @)

[ here the angle @ must be in radians - not degrees]

1) r = 1.5 m and @ = 0.43 radians
segment area = 0.5 x 1.5^2 x (0.43 - sin(0.43)) = 0.01477 m^2
just sub in and give results in m^2 units

2) r = 7.2 mm @ = (55/360) x 2 x pi radians
give results in mm^2 units

3) r = 2.1 m 35' = 35/60 deg = 0.58333 .. @ = (82.58333../360) x 2 x pi rads
Give results in m^2 units

4) Nothing could be easier since @ already given = pi/7 rads and r = 3 cm
give results in cm^2 units

If formula I gave is wrong, then all your answers will be wrong of course!