Question

what is the value of cos square 31 minus sin square 51​

Answer 1

Answer:

your question should be  cos square 39 minus sin square 51​

Step-by-step explanation:

=>  cos²(39) - sin²(51)

=>  cos²(39) - sin²(90 - 51)

=>  cos²(39) - cos²(39)

=>  0