Given \tanθ=815
sintheta=frac817,quadcostheta=frac1517 from pythagora's theorem.
To find fracsintheta−costhetasin2theta−sintheta
Numerator → sintheta−costheta=frac817−frac1517=frac−717
Denominator → sin2theta=left(frac817right)2=frac64289,quadsin2theta−sintheta=frac64289−frac136289=frac−72289
fracfrac−717frac−72289=frac7times28917times72=frac11972
