It is given that $\cos x=-\frac{5}{6}$. Using the form $\cos 2x=2{\cos }^{2}x-1$, find the exact value of $\cos 2x$.

Which single trigonometric value is equal to $2\sin 55^{\circ }\cos 55^{\circ }$?

Use a double-angle identity to find the exact value of $2\sin 105^{\circ }\cos 105^{\circ }$.

It is given that $\tan \alpha =-\frac{4}{3}$ and that $\alpha$ lies in the fourth quadrant. Find the exact value of $\tan 2\alpha$.

Use a double-angle identity to find the exact value of $2\sin 135^{\circ }\cos 135^{\circ }$.

It is given that $\sin \theta =-\frac{3}{5}$ and that $\theta$ lies in the third quadrant. Find the exact value of $\sin 2\theta$.

It is given that $\cos x=-\frac{3}{8}$. Using the form $\cos 2x=2{\cos }^{2}x-1$, find the exact value of $\cos 2x$.

Use a double-angle identity to find the exact value of $2\sin 45^{\circ }\cos 45^{\circ }$.

Use a double-angle identity to find the exact value of $2{\cos }^{2}120^{\circ }-1$.

Apply a double-angle identity to write $\cos 12x$ using the cosine of $6x$ alone. Which expression results?

It is given that $\cos x=\frac{2}{9}$. Using the form $\cos 2x=2{\cos }^{2}x-1$, find the exact value of $\cos 2x$.

It is given that $\cos x=\frac{4}{7}$. Using the form $\cos 2x=2{\cos }^{2}x-1$, find the exact value of $\cos 2x$.

Use a double-angle identity to find the exact value of $1-2{\sin }^{2}45^{\circ }$.

It is given that $\cos x=-\frac{3}{7}$. Using the form $\cos 2x=2{\cos }^{2}x-1$, find the exact value of $\cos 2x$.

It is given that $\tan \alpha =-\frac{8}{3}$ and that $\alpha$ lies in the fourth quadrant. Find the exact value of $\tan 2\alpha$.

Apply a double-angle identity to write $\cos 4x$ using the sine of $2x$ alone. Which expression results?

Which single trigonometric value is equal to $2{\cos }^{2}55^{\circ }-1$?

It is given that $\sin \theta =-\frac{3}{5}$ and that $\theta$ lies in the fourth quadrant. Find the exact value of $\sin 2\theta$.

Apply a double-angle identity to write $\cos 6x$ using the sine of $3x$ alone. Which expression results?

It is given that $\cos x=-\frac{3}{5}$. Using the form $\cos 2x=2{\cos }^{2}x-1$, find the exact value of $\cos 2x$.

It is given that $\tan \alpha =\frac{7}{4}$ and that $\alpha$ lies in the first quadrant. Find the exact value of $\tan 2\alpha$.

Apply a double-angle identity to write $\cos 10x$ using the sine of $5x$ alone. Which expression results?

It is given that $\sin \theta =-\frac{9}{41}$ and that $\theta$ lies in the fourth quadrant. Find the exact value of $\sin 2\theta$.

It is given that $\sin \theta =\frac{3}{5}$ and that $\theta$ lies in the first quadrant. Find the exact value of $\sin 2\theta$.

It is given that $\sin \theta =-\frac{20}{29}$ and that $\theta$ lies in the fourth quadrant. Find the exact value of $\sin 2\theta$.

It is given that $\tan \alpha =\frac{2}{3}$ and that $\alpha$ lies in the first quadrant. Find the exact value of $\tan 2\alpha$.

It is given that $\sin \theta =\frac{3}{5}$ and that $\theta$ lies in the second quadrant. Find the exact value of $\sin 2\theta$.

Which single trigonometric value is equal to $1-2{\sin }^{2}80^{\circ }$?

Use a double-angle identity to find the exact value of $2\sin 60^{\circ }\cos 60^{\circ }$.

It is given that $\tan \alpha =\frac{7}{5}$ and that $\alpha$ lies in the first quadrant. Find the exact value of $\tan 2\alpha$.

Which single trigonometric value is equal to $1-2{\sin }^{2}50^{\circ }$?

It is given that $\cos x=\frac{2}{3}$. Using the form $\cos 2x=2{\cos }^{2}x-1$, find the exact value of $\cos 2x$.

Which single trigonometric value is equal to $1-2{\sin }^2{5}^{\circ }$?

It is given that $\sin \theta =-\frac{5}{13}$ and that $\theta$ lies in the fourth quadrant. Find the exact value of $\sin 2\theta$.

Which single trigonometric value is equal to $2{\cos }^{2}35^{\circ }-1$?

It is given that $\sin \theta =-\frac{5}{13}$ and that $\theta$ lies in the third quadrant. Find the exact value of $\sin 2\theta$.

Apply a double-angle identity to write $\cos 4x$ using the cosine of $2x$ alone. Which expression results?

Which single trigonometric value is equal to $2{\cos }^{2}40^{\circ }-1$?

It is given that $\cos x=-\frac{1}{4}$. Using the form $\cos 2x=2{\cos }^{2}x-1$, find the exact value of $\cos 2x$.

Apply a double-angle identity to write $\sin 8x$ in terms of functions of $4x$. Which expression results?