Question

Help me to prove it

Answer 1

see explanation

Explanation:

Using the identities

cotA =
`(1)/(tanA)`

cot²A = cosec²A - 1

tan²A = sec²A - 1

Consider the left side

(cotA + tanA)² ← expand using FOIL

= cot²A + 2cotAtanA + tan²A

= cosec²A - 1 + 2 .
`(1)/(tanA)` . tanA + sec²A - 1

= cosec²A - 1 + 2 + sec²A - 1

= sec²A + cosec²A - 2 + 2

= sec²A + cosec²A

= right side, thus proven