sin x=1/3 find cos x

itzmetheguy:

sin x=1/3
find cos x

Draw a right angled triangle
mark the right angle and the x angle
put the 1 and the 3 in the right spots.
work out what the other side is
then
read cos x of the triangle.

The first answer was right, here is just another way to look at it/ remember it:

SOHCAHTOA
Sin = Opposite / Hypotenuse
Cosine = Adjacent / Hypotenuse
Tangent = Opposite / Adjacent

so if sin(x) = 1/3

then Opposite = 1, and Hypotenuse = 3

Hint: by pythagorean's theorem we know that Hypotenuse ² = Opposite ² + Adjacent ²

You already have Hypotenuse, so just solve for adjacent using the pythag. theorem and plug it into: cos(x) = A/H

Another easy way to convert sin to cos (and vice-versa):

sin(x) = 1/3

just look at the fraction: take the denominator squared, minus the numerator squared and take the square root of that whole thing. Divide that by the original denominator and there you have your cosine.

So: