How to Use SIN and COS in Excel

Split a force into horizontal and vertical parts with COS and SIN, then add a whole set of angled pulls in one formula.

You will learn to

• Find the horizontal part of an angled force
• Find the vertical part
• Add the horizontal pull of several ropes

How it works

SIN(number) and COS(number) return the sine and cosine of an angle given in radians. For an angle in degrees, convert first: =COS(RADIANS(30)) is 0.866. A force F at angle θ above horizontal has a horizontal part of F*COS(θ) and a vertical part of F*SIN(θ).

Both functions work on ranges, so =SUMPRODUCT(B2:B6,COS(RADIANS(C2:C6))) adds the horizontal pull of several angled ropes at once. The most common mistake is =SIN(30), which treats 30 as radians and returns -0.988 instead of 0.5.

=B2*COS(RADIANS(C2))