Question 773336
cos20degreescos30degrees-cos20degreessin30degrees
<pre>
cos(A+B) &#8801; cos(A)cos(B) - sin(A)sin(B)

Let A = 20° and B = 30°

cos(20°+30°) &#8801; cos(20°)cos(30°) - sin(30°)sin(20°)

Answer: cos(50°)

[Incidentally you can type the little circle degree mark °
by holding down the ALT key while you type 248 on the keypad
at the far right of your keyboard. When you let up the ALT
key the ° will appear on your screen.]

Edwin</pre>