Question

cos 2q = 1- tan square q upon 1 + tan square q​

Answer 1

Step-by-step explanation:

cos 2 q is equal to 1 minus tan squared Q upon 1 + 10 square q

lhs

cos 2 q =cos square q -sin square q

now divide a numerator and denominator by cos square q ,we will get

1 minus tan square q upon 1 + tan square q

hope it is clear to you

Answer 2

Step-by-step explanation:

cos 2q = cos(q + q)

⇒cos(2q) = cos q * cos q - sin q * sin q  [∵cos(x + y) = cos x * cos y - sin x * sin y]

⇒cos(2q) = cos q^{2} - sin q^{2}

⇒cos(2q) = cos q^{2} - sin q^{2} / cos q^{2} + sin q^{2}  [∵ cos q^{2} + sin q^{2} = 1]

Dividing each terms of numerator and denominator by cos q^{2} , we get-

cos(2q) = 1 - tan q^{2} / 1 + tan q^{2}

Hence, proved

Hope I helped you.

Please mark my answer as brainliest.

Thanks.