00:01
Hi, from the question given that cos x is equal to 2 by bhaer x in the quadrant 1.
00:22
So we know that in quadrant 1 all the technometry values are positive.
00:28
So first find sine x.
00:33
So sine x is equal to square root of 1 minus cos squared x.
00:40
Since we know that sine squared x plus cos squared x is equal to 1.
00:51
Now, sine x is equal to square root of 1 minus cos squared x is 2 by 3 the old square.
01:01
So, simplified further, we obtain 1 minus 4 by 9.
01:07
So 9 minus 4 is 5, 5 by 9.
01:10
So under root of 5 divided by 3.
01:15
So when we're taking square root, it will have a plus or minus symbol.
01:21
But we know that in first quadrant, all the trigonometry values are positive.
01:26
So only we assume positive values.
01:28
Now, first we need to find sine 2x.
01:35
So this could be equal to 2 sine x cos x.
01:41
So here, sine x is equal to root 5 by 3 and cos x is equal to 2 by 3...