Question

find the value of cos(29π/3)​

Answer 1

Step-by-step explanation:

cos{(27+2)π/3}

cos{(27+2)π/3}= cos (9π+2π/3)

cos{(27+2)π/3}= cos (9π+2π/3)= - cos2π/3

cos{(27+2)π/3}= cos (9π+2π/3)= - cos2π/3= - cos{π/2+π/6}

cos{(27+2)π/3}= cos (9π+2π/3)= - cos2π/3= - cos{π/2+π/6}= sinπ/6= 1/2

Answer 2

Answer:

Step-by-step explanation:

Concept:

Here the concept of trigonometry will be used to solve this question.

Given :

The expression is $\cos (29 \pi / 3)$ which we need to solve.

To Find:

We need to find the value of $\cos (29 \pi / 3)$ .

Solution:

We can write the expression as: $\cos (29 \pi / 3) = \cos \left(\frac{(27+2) \pi}{3}\right)$.

After dividing by $3$ , the expreesion will be $\cos \left(9 \pi+\frac{2 \pi}{3}\right)$ .

Therefore, we will get $-\cos \frac{2 \pi}{3}$ .

We need to divide $\frac{2 \pi}{3}$ .So, we can write $-\cos \frac{2 \pi}{3} =-\cos \left(\frac{\pi}{2}+\frac{\pi}{6}\right)$ .

The final expression is $\sin \frac{\pi}{6}$ .

$\frac{\pi}{6}$ can be written as $30^{\circ}$ .

The value of $\sin 30^{\circ}=\frac{1}{2}$ .

The value of $\cos (29 \pi / 3)$ is $\frac{1}{2}$ .

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