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

Popular >

2cos^2(pi/2)

2 cos^{2} (\frac{π}{2})

0

Solution steps

2 cos^{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

= 2 \cdot 0^{2}

Simplify

= 0

\frac{tan ( 1 9 ^{\circ} ) + tan ( 4 7 ^{\circ} )}{1 - tan ( 1 9 ^{\circ} ) tan ( 4 7 ^{\circ} )}

arctan (\frac{- 3}{5})

cos (14 0^{\circ}) cos (2 0^{\circ}) - sin (14 0^{\circ}) sin (2 0^{\circ})

- 3 sin (\frac{π}{4})

tan (arcsin (0))