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Prove the following identity ​

Prove the following identity ​-example-1

1 Answer

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Answer:

sec(x)/(tan xsin(x))=cot^2 x+1 = Ture

Explanation:

Verify the following identity:

sec(x)/(tan(x) sin(x)) = cot(x)^2 + 1

Hint: | Eliminate the denominator on the left hand side.

Multiply both sides by sin(x) tan(x):

sec(x) = ^?sin(x) tan(x) (cot(x)^2 + 1)

Hint: | Express both sides in terms of sine and cosine.

Write cotangent as cosine/sine, secant as 1/cosine and tangent as sine/cosine:

1/cos(x) = ^?sin(x)/cos(x) sin(x) ((cos(x)/sin(x))^2 + 1)

Hint: | Simplify the right hand side.

((cos(x)/sin(x))^2 + 1) sin(x) (sin(x)/cos(x)) = (((cos(x)^2)/(sin(x)^2) + 1) sin(x)^2)/(cos(x)):

1/cos(x) = ^?(sin(x)^2 (cos(x)^2/sin(x)^2 + 1))/cos(x)

Hint: | Put the fractions in cos(x)^2/sin(x)^2 + 1 over a common denominator.

Put cos(x)^2/sin(x)^2 + 1 over the common denominator sin(x)^2: cos(x)^2/sin(x)^2 + 1 = (cos(x)^2 + sin(x)^2)/sin(x)^2:

1/cos(x) = ^?sin(x)^2/cos(x) (cos(x)^2 + sin(x)^2)/sin(x)^2

Hint: | Cancel down ((cos(x)^2 + sin(x)^2) sin(x)^2)/(sin(x)^2 cos(x)).

Cancel sin(x)^2 from the numerator and denominator. ((cos(x)^2 + sin(x)^2) sin(x)^2)/(sin(x)^2 cos(x)) = (sin(x)^2 (cos(x)^2 + sin(x)^2))/(sin(x)^2 cos(x)) = (cos(x)^2 + sin(x)^2)/cos(x):

1/cos(x) = ^?(cos(x)^2 + sin(x)^2)/cos(x)

Hint: | Eliminate the denominators on both sides.

Multiply both sides by cos(x):

1 = ^?cos(x)^2 + sin(x)^2

Hint: | Use the Pythagorean identity on cos(x)^2 + sin(x)^2.

Substitute cos(x)^2 + sin(x)^2 = 1:

1 = ^?1

Hint: | Come to a conclusion.

The left hand side and right hand side are identical:

Answer: (identity has been verified)

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