What an Identity Is Worksheet with Answer Key

What's on the worksheet

1. Classify each equation as an identity, a conditional equation, or an equation with no solution.
   \sin(t + 2\pi) - \sin(-t) = 2\sin t\sin(\pi - t) = \sin t\sin t + \cos t = 3\tan(t + \pi) = \tan t\sin t\cos(-t) = \sin(-t)\cos t
2. None of these equations is an identity.
   \sin t\cos t = \sin t\dfrac{1}{\cos t} = \cos t\cos^2 t - \sin^2 t = 1(\sin t + \cos t)^2 = 1
3. The equation | t| = t is not an identity on all real numbers.
4. Each equation is an identity.
5. Yuna checks the equation (-t) = t at t = 0, t = π2 and t = π, and it holds each time.