Differentials to estimate sin 28

[Sophie]

Use differentials or linear approximation to estimate sin 28.

sinx = y =f(x)

when x =30 dx = -2

dy =(cosx) (dx)

dy = (cos 30) (-Pi/90) = ((sqrt3)/2) * (-Pi/90) = -0.03

sin 28 = f(28) = f(30) + dy/dx = (1/2) -0.03 = 0.47

Can someone please check this, thanks Sophie

 

[skeeter]

check it yourself ... get out your calculator and see what you get for the sine of 28 degrees.