00:01
Here in this problem we have given sine theta is equal to minus 12 upon 13 where theta is greater than 270 degree and smaller than 360 degree and we are asked to find the exact value of sine 2 theta cosine 2 theta and tangent 2 theta now for calculating the value of cosine 2 theta we will apply the formula cosine 2 theta is equal to 1 minus 2 into sin square theta by substituting the value of sine theta we get cosine 2 theta is equal to 1 minus 2 into minus 12 upon 13 whole square.
00:46
Further we get cosine 2 theta is equal to 1 minus 288 upon 169.
00:56
By simplifying it we get cosine 2 theta is equal to 169 minus 288 upon 169.
01:08
By simplifying it we get cosine 2 theta is equal to minus 119.
01:20
Now in order to find the value of sine 2 theta, first of all we will find the value of cosine theta.
01:28
By using the formula, cosine square theta is equal to 1 plus cosine 2 theta upon 2.
01:38
By substituting the value of cosine 2 theta we get cosine square theta is equal to 1 minus 119 upon 169 upon 2.
01:52
Further we get cosine square theta is equal to 169 minus 119 upon 2 into 169.
02:05
By simplifying it we get cosine square theta is equal to 25 upon 169.
02:12
By taking the square root we get cosine theta is equal to 5 upon 30...