If sin245−sin260=xcos245 then x= ..............
sin245−sin260=xcos245⇒(1√2)2−(√32)2=x(1√2)2⇒(√22)2−(√32)2=x(√22)2⇒24−34=2x4
⇒2−34=2x4⇒−14=2x4
⇒−1=2x⇒x=−12
Hence, Option C is correct.