Question

If sin θ = 15 over 17, use the Pythagorean Identity to find cos θ.

Answer 1

Remember SOH CAH TOA
sin=opposite/hypotenuse
cos=Adjacent/Hypotenuse
Tan=Opposite/Over Adjacent

So from the problem:
Sin=15/17
which by SOH CAH TOA means cos = x/17
because this is a right triangle you can do:

`\sqrt{17^(2)-{15^(2)=x`

so cos =
`\sqrt{17^(2)-{15^(2)/17`

Answer 2

cos (theta) = +/- 8/17

Explanation:

Use the definition of cosine to find the value of cos (theta)

cos (theta)=adj/hyp

Substitue in the known values

cos (theta)=+/- 8/17