If sin²A+cos²A=1 and tanA=2, find sinA and cosA.
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Correct answer: A
Explanation
Has been given :
sin²A + cos²A = 1
tanA = 2
According to the formula:
tanA = sinA / cosA
tanA = 2
sinA / cosA = 2
sinA = 2cosA
sin²A + cos²A = 1
(2cosA)² + cos²A = 1
4cos²A + cos²A = 1
5cos²A = 1
cos²A = 1/5
cosA = 1/√5
sinA = 2/√5
sinA = 2/√5 , cosA = 1/√5