What is the value of 3cos(-pi/2) ?

English

Español

Português

Français

Deutsch

Italiano

Русский

中文(简体)

한국어

日本語

Tiếng Việt

עברית

العربية

Popular >

3cos(-pi/2)

3 cos (- \frac{π}{2})

0

Solution steps

3 cos (- \frac{π}{2})

Rewrite using trig identities:

cos (- \frac{π}{2}) = 0

cos (- \frac{π}{2})

Use the following property:

cos (- x) = cos (x)

cos (- \frac{π}{2}) = cos (\frac{π}{2})

= cos (\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

= 0

= 3 \cdot 0

Simplify

= 0

sin (\frac{7 π}{12}) - sin (\frac{π}{12})

\frac{cos ( 2 )}{2}

cos (0) + i sin (0)

5 sin (32 0^{\circ})

- 6 sin (\frac{π}{4})