The video tutorial explains how to use the Pythagorean identity to rewrite cosine in terms of sine. It begins by introducing the identity and then demonstrates solving for cosine. The instructor simplifies the expression by plugging in values and removing parentheses, ultimately verifying that the left side of the equation equals the right side.

What does the Pythagorean identity state in terms of cosine and sine?

• Cosine squared of beta minus sine squared of beta equals one.

• Cosine squared of beta plus sine squared of beta equals one.

• Cosine of beta minus sine of beta equals one.

• Cosine of beta plus sine of beta equals one.

How can cosine squared be expressed using sine squared?

• Cosine squared equals sine squared plus one.

• Cosine squared equals one minus sine squared.

• Cosine squared equals sine squared minus one.

• Cosine squared equals one plus sine squared.

What is the result of simplifying the expression 1 - 2 sine squared of beta?

• It equals cosine squared of beta.

• It equals zero.

• It equals sine squared of beta.

• It equals one.

Which step involves getting rid of the parentheses in the expression?

• When substituting values into the equation.

• When simplifying the expression to show equality.

• When rewriting cosine in terms of sine.

• When initially stating the Pythagorean identity.

What is the final conclusion of the proof using the Pythagorean identity?

• The left side is less than the right side.

• The left side is unrelated to the right side.

• The left side is greater than the right side.

• The left side equals the right side.