Cos(3theta/5, plus 11°) = sin(7theta/10, plus 40°) find solution

Question

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Answer 1

Use the cofunction identity:  sinα = cos(90°-α)

 

So, 3θ/5 + 11 + 7θ/10 + 40 = 90

 

      3θ/5 + 7θ/10 = 39

 

        6θ + 7θ = 390

 

               13θ = 390

 

                  θ = 30°