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

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

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cos^2(pi/2)-sin^2(pi/2)

cos^{2} (\frac{π}{2}) - sin^{2} (\frac{π}{2})

- 1

Solution steps

cos^{2} (\frac{π}{2}) - sin^{2} (\frac{π}{2})

Use the following trivial identity:

cos (\frac{π}{2}) = 0

cos (\frac{π}{2})

cos (x)

periodicity table with

2 πn

cycle:

x 0 \frac{π}{6} \frac{π}{4} \frac{π}{3} \frac{π}{2} \frac{2 π}{3} \frac{3 π}{4} \frac{5 π}{6} cos (x) 1 \frac{3}{2} \frac{2}{2} \frac{1}{2} 0 - \frac{1}{2} - \frac{2}{2} - \frac{3}{2} x π \frac{7 π}{6} \frac{5 π}{4} \frac{4 π}{3} \frac{3 π}{2} \frac{5 π}{3} \frac{7 π}{4} \frac{11 π}{6} cos (x) - 1 - \frac{3}{2} - \frac{2}{2} - \frac{1}{2} 0 \frac{1}{2} \frac{2}{2} \frac{3}{2}

= 0

Use the following trivial identity:

sin (\frac{π}{2}) = 1

sin (\frac{π}{2})

sin (x)

periodicity table with

2 πn

cycle:

x 0 \frac{π}{6} \frac{π}{4} \frac{π}{3} \frac{π}{2} \frac{2 π}{3} \frac{3 π}{4} \frac{5 π}{6} sin (x) 0 \frac{1}{2} \frac{2}{2} \frac{3}{2} 1 \frac{3}{2} \frac{2}{2} \frac{1}{2} x π \frac{7 π}{6} \frac{5 π}{4} \frac{4 π}{3} \frac{3 π}{2} \frac{5 π}{3} \frac{7 π}{4} \frac{11 π}{6} sin (x) 0 - \frac{1}{2} - \frac{2}{2} - \frac{3}{2} - 1 - \frac{3}{2} - \frac{2}{2} - \frac{1}{2}

= 1

= 0^{2} - 1^{2}

Simplify

= - 1

cos^{2} (\frac{7 π}{8}) - sin^{2} (\frac{7 π}{8})

sin (\frac{11 π}{20}) cos (\frac{π}{5}) + cos (\frac{11 π}{20}) sin (\frac{π}{5})

cot (arccos (- \frac{5}{6}))

arcsin (0.549)

tan (0.02)

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