Question

A student begins a proof of the law of cosines. His work is shown.

Answer 1

The student made an error in step 3. To correct this error, he should define side AY in terms of angle X. Pythagorean theorem relates sides x, y, z, and angle X

The law of cosine.

In Trigonometry, law of cosine (cos) is given by this mathematical expression:

cosθ = Opp/Hyp

Where:

• Opp is the opposite side of a right-angled triangle.

• Hyp is the hypotenuse of a right-angled triangle.

• θ is the angle.

In this scenario, we can logically deduce that the student made an error in step 3. To correct this error, he should define side AY in terms of angle X.

After correcting this error, the student can use the Pythagorean theorem to relate sides x, y, z, and angle X.

Read more on law of cosine here: brainly.com/question/27613782

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