How do we solve this please ?

Question

sin² x - cos(pi/2 - x) - 2sin(pi - x) +3

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Answer 1 · 2018-05-06T18:42:43

Using the complementary and supplementary angle rules,

# sin ^2 x - cos(pi/2 -x) - 2 sin (pi - x) + 3 ##= sin ^2 x - 3sin x - 3 #

It's not an equation so it's not really something to solve. Maybe that last plus is supposed to be an equals sign -- same key on the keyboard.

Let's simplify the expression as typed,

# sin ^2 x - cos(pi/2 -x) - 2 sin (pi - x) + 3 #

The cosine of a complementary angle is the sine of the original angle. The sine of a supplementary angle equals the sine of the original angle.

# = sin ^2 x - sin x - 2 sin x + 3 #

#= sin ^2 x - 3sin x + 3 #

We'll leave it there until the question is edited.