Trig problems in Excel?

Question

The problem given is sin(x)/1 = sin (30)/10
Supposedly I can get the right answer by writing the formula for arcsin (1*sin(30)/10)*(180/pi) (for degrees instead of radians.
My answer is supposed to be 2.9, but Excel keeps giving me the answer -5.67.
This is what I am typing into excel: asin(1*sin(30)/10)*180/pi()

Answer 1

sinx=sin(30)/10

If 30 is degrees, then sin30/10=1/20 and x= sin-1(1/20)= 2.866 degrees

If 30 is radians, then sin30/10= -.0988 and x=sin-1(-.0988) = -.0990 radians

To convert degrees to radians, d*(pi/180)=r

Answer 2

I take it that your given angle is in degrees, and you want the answer in degrees too. You need to effect a unit conversion twice. The angle is converted to radians in the argument of the sine function. The arcsine function will render an answer in radians, which needs to be converted to degrees.



This is what should be entered in the cell:



=ASIN(SIN(30*PI()/180)/10)*180/PI()

Answer 3

The argument used in Excel's sin function is in radians, not degrees. You can use SIN(RADIANS(30)).