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Popular >

cos(-pi/5)

Solution

cos (- \frac{π}{5})

Solution

\frac{5 + 1}{4}

+1

Solution steps

cos (- \frac{π}{5})

Use the following property:

cos (- x) = cos (x)

cos (- \frac{π}{5}) = cos (\frac{π}{5})

= cos (\frac{π}{5})

Rewrite using trig identities:

\frac{5 + 1}{4}

= \frac{5 + 1}{4}

Popular Examples

csc (- \frac{7 π}{9})

sec (\frac{- 7 π}{6})

ln(2+sin((11pi)/6))

ln (2 + sin (\frac{11 π}{6}))

cos (4 5^{\circ} + 15 0^{\circ})

cos(45)+sin(45)

cos (4 5^{\circ}) + sin (4 5^{\circ})

Frequently Asked Questions (FAQ)

What is the value of cos(-pi/5) ?
The value of cos(-pi/5) is (sqrt(5)+1)/4