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Double angles

Find sin2x, cos2x, and tan 2x under the given conditions.
23. sinx=5/13 (0<x<pie/2)

sin 2x = 120/169, cos 2x = 119/169, tan 2x = 120/119

Please explain in detail step by step how to come up with this ans.

25. cos x=-3/5 (pie<x< 3pie/2)

ans. sine 2x=24/25, cos2x=-7/25, tan2x=-24/7

Solution Preview

23. Since sinx=5/13, then cosx=sqrt(1-(5/13)^2)=12/13
Then we can get

Solution Summary

This shows how to find the value of cos, sin, and tan of 2x for a given value of sin x.