Question

please explain this step by step with reason fast!!​

Answer 1

Answer:

19/2

Step-by-step explanation:

sin²5+sin²10+sin²15+sin²20+sin²25.+sin²30+sin²35+sin²40+sin²45+sin²50+sin²55+sin²60+sin²65+sin²70+sin²75+sin²80+sin²85    +sin²90

=sin²(90-85)+sin²(90-80)+sin²(90-75)+sin²(90-70)+sin²(90-65)+sin²(90-60)+sin²(90-55)+sin²(90-50) +sin²45+sin²50+sin²55+sin²60+sin²65+sin²70+sin²75+sin²80+sin²85++sin²90.

=cos²85+cos²80+cos²75+cos²70+cos²65+cos²60+cos²55+cos²50+sin²45+.sin²50+sin²55+sin²60+sin²65+sin²70+sin²75+sin²80+sin²85 +1

=1*8+(1/√2)²+1

=8+1/2+1

=9+1/2

=19/2