1.

5. Evaluate sin18º.cos72° + cos18. sin 72°.​

Answer»

Answer:

cos18

o

sin12

o

+sin18

o

cos72

o

= COS(90

o

72

o

)sin72

o

+sin(90

o

–72

o

)cos72

o

= sin72

o

.sin72

o

+cos72

o

cos72

o

=sin

2

72

o

+cos

2

72

o

=1

(∵sin

2

θ+cos

2

θ)



Discussion

No Comment Found

Related InterviewSolutions