How do you prove sec^2(csc^2) = sec^2 + csc^2?
2 Answers
May 4, 2016
see below
Explanation:
Right Side:
May 4, 2016
Note the following identity:
csc^2theta = 1 + cot^2theta
So, let's see how that works out.
\mathbf(sec^2theta(csc^2theta) = sec^2theta + csc^2theta)
sec^2theta(1 + cot^2theta) = sec^2theta + csc^2theta
sec^2theta + sec^2thetacot^2theta = sec^2theta + csc^2theta
Lastly, use the identities
cot^2theta = cos^2theta/sin^2theta, 1/sin^2theta = csc^2theta, 1/cos^2theta = sec^2theta,
to get:
sec^2theta + sec^2theta(cos^2theta/sin^2theta) = sec^2theta + csc^2theta
sec^2theta + 1/cancel(cos^2theta)(cancel(cos^2theta)/sin^2theta) = sec^2theta + csc^2theta
sec^2theta + 1/sin^2theta = sec^2theta + csc^2theta
color(blue)(sec^2theta + csc^2theta = sec^2theta + csc^2theta)