# If and x lies in IInd quadrant, find the values of and

Given:

We know,

sin2 x + cos2 x = 1

cos2 x = 1 – sin2 x

Since,

cosx will be negative in second quadrant

So,

We know,

cos 2x = 2 cos2 x – 1

Since,

So,

We know,

cos 2x = 1 – 2 sin2 x

Since,

So,

We know,

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