Question

cos²Acos²B+sin²Asin²B=1 please prove it.​

Answer 1

Answer:

cos^2A cos^2B + sin ^2A sin ^2B

(cos^2A+sin^2A). (cos^2B+sin ^2B )

we have formula ,

sin^2 theta +cos ^2 thete =1 ,

so by using this formula we get

(1). (1) =1 hence it is prooved and remeber ^2 mean square . theta means angle