Question

Find the value of -sin theta cos theta (90-theta)+cos theta sin (90-theta)

Answer 1

Hiii friend,


Sin theta × Cos (90-Theta) + Cos theta × Sin(90-theta)


=> Sin theta × Sin theta + Cos theta × Cos theta


=> Sin²theta + Cos²theta = 1



HOPE IT WILL HELP YOU....... :-)

Answer 2

Answer:

Sin²Ф + Cos²Ф = 1

Step-by-step explanation:

To find the value of given trigonometric

According to the trigonometric,

Cos (90-Ф) = -SinФ

=> -SinФ × Cos (90-Ф) + Cos Ф × Sin(90-Ф)

= - Sin Ф × (-Sin Ф) + Cos Ф × Cos Ф

=  Sin²Ф + Cos²Ф = 1

This is the first identity of the trigonometry.