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Popular >

cos^2(180)

Solution

cos^{2} (18 0^{\circ})

Solution

1

Solution steps

cos^{2} (18 0^{\circ})

Use the following trivial identity:

cos (18 0^{\circ}) = (- 1)

cos (18 0^{\circ})

cos (x)

periodicity table with

36 0^{\circ} n

cycle:

x 0 3 0^{\circ} 4 5^{\circ} 6 0^{\circ} 9 0^{\circ} 12 0^{\circ} 13 5^{\circ} 15 0^{\circ} cos (x) 1 \frac{3}{2} \frac{2}{2} \frac{1}{2} 0 - \frac{1}{2} - \frac{2}{2} - \frac{3}{2} x 18 0^{\circ} 21 0^{\circ} 22 5^{\circ} 24 0^{\circ} 27 0^{\circ} 30 0^{\circ} 31 5^{\circ} 33 0^{\circ} cos (x) - 1 - \frac{3}{2} - \frac{2}{2} - \frac{1}{2} 0 \frac{1}{2} \frac{2}{2} \frac{3}{2}

= (- 1)

= (- 1)^{2}

Simplify

(- 1)^{2} : 1

(- 1)^{2}

Apply exponent rule:

(- a)^{n} = a^{n},

if

n

is even

(- 1)^{2} = 1^{2}

= 1^{2}

Apply rule

1^{a} = 1

= 1

= 1

Popular Examples

sec(arcsin(-1/2))

sec (arcsin (- \frac{1}{2}))

tan (2 2^{\circ})

cos (arcsin (0))

-cos(pi)+cos(0)

- cos (π) + cos (0)

1 - sin (\frac{π}{2})

Frequently Asked Questions (FAQ)

What is the value of cos^2(180) ?
The value of cos^2(180) is 1