SOLUTION: Find sin2b if sin b = 7/25

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Question 993791: Find sin2b if sin b = 7/25
Answer by ikleyn(52798) About Me  (Show Source):
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Find sin2b if sin b = 7/25
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Is my understanding correct that you want to find  sin(2b)?

If so,  use the formula   sin(2b) = 2*sin(b)*cos(b).

Do you know this formula?

To complete calculations,  you need to know  cos(b)  too.
You can calculate it via  sin(b):

cos(b) = sqrt%281+-+sin%5E2%28b%29%29 = sqrt%281+-+%287%2F25%29%5E2%29 = sqrt%281-%2849%2F625%29%29 = sqrt%28%28625-49%29%2F625%29 = sqrt%28576%2F625%29 = 24%2F25.

Now you are ready to calculate

sin(2b) = 2*sin(b)*cos(b) = 2.7%2F25.24%2F25 = . . .

Please complete this calculation yourself.