Question

21 .... plz do it ... correct answer will be marked as brainliest and his or her account will be followed ​

Answer 1

Step-by-step explanation:

(SinA + CosecA)² + (CosA + SecA)²

=> (Sin²A + Cosec²A + 2SinACosecA) + (Cos²A + Sec²A + 2CosASecA)

Because (A + B)² = A² + B² + 2AB

=> (Sin²A + Cosec²A + 2SinA(1/SinA)) + (Cos²A + Sec²A + 2CosA(1/CosA))

Because CosecA = 1/SinA ; SecA = 1/CosA

=> (Sin²A + Cosec²A + 2(1)) + (Cos²A + Sec²A + 2(1))

=> Sin²A + Cosec²A + 2+ Cos²A + Sec²A + 2

=> (Sin²A + Cos²A) + Cosec²A + Sec²A + 4

=> (1) + Cosec²A + Sec²A + 4

because Sin²A + Cos²A = 1

=> 5 + (1 + cot²A) + (1 + tan²A)

because Cosec²A = 1 + cot²A , Sec²A = 1 + tan²A

=> 7 + Cot²A +  Tan²A

Hence Proved

REQUEST:

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