How do you solve sec^2(theta) - sin^2(theta) - cos^2(theta) - tan^2(theta) = 0?

1 Answer
Oct 9, 2016

Substitute identities and combine like terms to obtain: 0 = 0

Explanation:

Substitute 1 + tan²(theta) for sec²(theta):

1 + tan²(theta) - sin²(theta) - cos²(theta) - tan²(theta) = 0

Combine like terms:

1 - sin²(theta) - cos²(theta) = 0

Substitute 1 - cos²(theta) for sin(theta):

1 - (1 - cos²(theta)) - cos²(theta) = 0

Distribute the minus sign:

1 - 1 + cos²(theta) - cos²(theta) = 0

Combine like terms:

0 = 0