Question

Find the value of ....the following...​

Answer 1

Answer:

1

Step-by-step explanation:

Since Sin²∅+cos²∅=1

cos²72° + sin²72° = sin²72° + cos²72° = 1

here ∅=72°

Answer 2

Step-by-step explanation:

cos²72° + sin²72°

sin²(90°-72°) +sin²72°

sin²18°+sin²72°

sin²90°

1