What is the value of 1.2cos(30) ?

The value of 1.2cos(30) is (3sqrt(3))/5

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1.2cos(30)

1.2 cos (3 0^{\circ})

\frac{3 3}{5}

Decimal Notation

1.03923 \dots

Solution steps

1.2 cos (3 0^{\circ})

= \frac{6}{5} cos (3 0^{\circ})

Use the following trivial identity:

cos (3 0^{\circ}) = \frac{3}{2}

cos (3 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}

= \frac{3}{2}

= \frac{6}{5} \cdot \frac{3}{2}

Simplify

\frac{6}{5} \cdot \frac{3}{2} : \frac{3 3}{5}

\frac{6}{5} \cdot \frac{3}{2}

Cross-cancel common factor:

2

= \frac{3}{5} \cdot \frac{3}{1}

Multiply fractions:

\frac{a}{b} \cdot \frac{c}{d} = \frac{a \cdot c}{b \cdot d}

= \frac{3 3}{5 \cdot 1}

Multiply the numbers:

5 \cdot 1 = 5

= \frac{3 3}{5}

= \frac{3 3}{5}

tan (7 0^{\circ}) + cot (2 0^{\circ}) - 2 tan (7 0^{\circ})

50 cos (3 8^{\circ})

arctan ((tan (1^{\circ}))^{2} + (tan (4^{\circ}))^{2})

cos^{2} (\frac{5 π}{4}) - sin^{2} (\frac{2 π}{3})

50 sin (5 3^{\circ})