Question

sin 55x cos35
solve by the formula
sinA x cosB=1/2[sin(A+B)+sin(A-B)]​

Answer 1

Answer:

sin55 x cos 35 = 1/2 [ sin (55+35) + sin (55-35)]

=1/2(sin 90+ sin 20)

=1/2 (1 + sin 20 ) {sin 20= 0.34 }

=1/2 (1+0.34)

= 1/2 x 1.34

= 0.67