Question

cos square 20 + cos square 70 upon sin squared theta minus cos squared into 2sec square 60

Answer 1

Answer:

Step-by-step explanation:

Answer 2

Answer:

8

Step-by-step explanation:

cos^2(70) = cos^(90-20) = sin^2(20)

therefore, cos^2(20) + sin^2(20)=1

1 + cot^2(theta)=sec^2(theta) ===> denominator  also become 1

left =2sec^2(60) = 2/cos^2(60) = 2/ (1/2)^2  = 2*4 = 8