How do you simplify sin2x×sin7x? Trigonometry Trigonometric Identities and Equations Fundamental Identities 1 Answer Andrea S. Dec 1, 2016 Use the exponential form of the trigonometric functions: sin(7x)=e7ix−e−7ix2i sin(2x)=e2ix−e−2ix2i sin(2x)sin(7x)=e7ix−e−7ix2ie2ix−e−2ix2i= =e9ix−e5ix−e−5ix+e−9ix(2i)2=e5ix+e−5ix4−e9ix+e−9ix4 sin(2x)sin(7x)=cos(5x)−cos(9x)2 Answer link Related questions How do you use the fundamental trigonometric identities to determine the simplified form of the... How do you apply the fundamental identities to values of θ and show that they are true? How do you use the fundamental identities to prove other identities? What are even and odd functions? Is sine, cosine, tangent functions odd or even? How do you simplify secxcos(π2−x)? If cscz=178 and cosz=−1517, then how do you find cotz? How do you simplify sin4θ−cos4θsin2θ−cos2θ using... How do you prove that tangent is an odd function? How do you prove that sec(π3)tan(π3)=2√3? See all questions in Fundamental Identities Impact of this question 6516 views around the world You can reuse this answer Creative Commons License