Question

cos 5° - sin 25° is equal to
(a) sin 20°
(b) sin 30
(c) sin 35°
(d) sin 60°
The person who gives right answer i will mark as brainlist​

Answer 1

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L.H.S = cos5 – sin 25

= sin 95 – sin 25 [ sin(90+5) = cos5 ]

= 2 * cos (95+25)/2 * sin (95-25)/22 * cos60 * sin35

=2 * ½ * sin35 (cos60 = ½ )

= sin35

= R.H.S

hence L.H.S = R.H.S

Answer 2

Answer:

sin 35°

Step-by-step explanation:

sin(90-85)-sin 25°

sin 85°-sin 25°

• (use sinx - siny formula)

and then get cos 55°

sin(90-35)

sin 35°