Question

8 TanA=15, then find SinA- CosA *

8/17

17/7

1/17

7/17

Other:



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Answer 1

Answer:

using tan²A+ 1 = sec²A

Step-by-step explanation:

8 tan A = 15

tan A = 15/8

squaring both sides

tan²A = 225/64

sec²A - 1 = 225/ 64

sec²A = 225/64 +1

sec² A = 225+ 64/ 64

sec²A =289/64

sec A = √289/√64

sec A = 17 /8

cos A = 8/17

squaring both sides

cos²A = 64/289

1 - sin²A = 64/289

1 - 64/289 = sin²A

sin²A = 289 - 64/ 289

sin²A = 225/289

sin A = 15/17

sin A - cos A

15/17 - 8/17

15 - 8

17

7/17