Question

cosA^4 - sinA^4 = ???​

Answer 1

Step-by-step explanation:

LHS =

(cos A)4 - (sin A)4

= [(cos A)2 - (sin A)2 ][(cos A)2 + (sin A)2 ] ..............................{ a2 - b2 = (a+b)(a-b) }

= (cos A)2 - (sin A)2 ............................. { [(cos A)2 + (sin A)2 ] = cos2A + sin2A = 1}

Answer 2

Answer:

cos⁴A-sin⁴A

(cos²A+sin²A)(cos²A-sin²A)

1.(cos²A-sin²A)

cos2A

this is your answer ❣️❣️✌️✌️