Answer is -28.37
Step-by-step explanation:
from the numerator cos 2a×cos 3a - cos 2a×cos7a= cos6a^2 -cos 14a^2
= -cos8a^2 for the numerator
from the denominator;
sin4a×sin3a-sin2a×sin5a= sin12a^2 -sin10a^2
= sin2a^2
therefore, combining the equation it gives; -cos8a^2/sin2a^2
a^2 will divide each other,
= -cos8/sin2.
from the calculator,
= - 0.9903/0.0349
= -28.37
