Question

1) Cos (40-theta) - Sin (50-theta) + Cos ²40+Cos²50°/
Sin²40° +sin²50​

Answer 1

Step-by-step explanation:

We shall use a conversion identity here: sin (90 deg - x) = cos x … (1)

So, here we go:

cos (40 deg - x) - sin (50 deg + x) = cos (40 deg - x) - sin (90 deg -(40 deg - x))

=> cos (40 deg - x) - sin (50 deg + x) = cos (40 deg - x) - cos (40 deg - x) [from (1)]

Therefore, cos (40 deg - x) - sin (50 deg + x) = 0, which is the required equation.

PS: I have used ‘deg’ instead of the symbol for degree and ‘x’ instead of theta cuz i don’t have the option of special character input.