Question

Use double angle formulas to find the exact value of sin2x,cos2x, and tan2x

sinx=12/13, 0<x<pi/2

Answer 1

sin2x = 2sinxcosx;
cos2x = (cosx)^2 - (sinx)^2;
tan2x = (sin2x)/(cos2x);

cosx = 5/13 from formula (sinx)^2 + (cosx)^2 = 1;

=> sin2x = 120/169;
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