What is the value of cos^2(60)-sin^2(60) ?

The value of cos^2(60)-sin^2(60) is -1/2

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cos^2(60)-sin^2(60)

cos^{2} (6 0^{\circ}) - sin^{2} (6 0^{\circ})

- \frac{1}{2}

Solution steps

cos^{2} (6 0^{\circ}) - sin^{2} (6 0^{\circ})

Use the following trivial identity:

cos (6 0^{\circ}) = \frac{1}{2}

Use the following trivial identity:

sin (6 0^{\circ}) = \frac{3}{2}

= (\frac{1}{2})^{2} - (\frac{3}{2})^{2}

Simplify

(\frac{1}{2})^{2} - (\frac{3}{2})^{2} : - \frac{1}{2}

= - \frac{1}{2}

cos (1 8^{\circ}) sin (- 7 2^{\circ})

arccos (\frac{5}{10})

sin (\frac{3 π}{10}) - sin (\frac{π}{10})

sin (\frac{6}{8})

arccos (7)

What is the value of cos^2(60)-sin^2(60) ?
The value of cos^2(60)-sin^2(60) is -1/2