Select the correct answer from each drop-down menu. A student begins a proof of the law of cosines. His work is shown.
Y
Z
X
x
Z
zcos(X) A
у
Step 1: cos(X) = AX 쌀
zcos(X) = AX
The next step in the proof is to write an expression for the length of side AZ in terms of
Then the student should write an expression for the length of side AY in terms of
Next he can use the
to relate x, y, z, and