Math / TrigonometryQuestionUse an addition or subtraction formula to write the expression as a trigonometric function of one number: cos3π7cos2π21+sin3π7sin2π21=cosπA=B2\cos \frac{3 \pi}{7} \cos \frac{2 \pi}{21}+\sin \frac{3 \pi}{7} \sin \frac{2 \pi}{21}=\cos \frac{\pi}{A}=\frac{B}{2}cos73πcos212π+sin73πsin212π=cosAπ=2B. B=B=B=Studdy SolutionA=3A = 3A=3 and B=1B = 1B=1.View Full Solution - FreeWas this helpful?