Question

Cos25°•cos15°-sin25°•sin15°/cos100°+cos20°

Answer 1

(cos25*cos15-sin25*sin15) / (cos100+cos20) = cos40/2cos60cos40=1/2cos60=1 делить на 1=1

Answer 2

To simplify the expression, let's break it down step by step:

1. Start with the numerator: cos(25°) • cos(15°) - sin(25°) • sin(15°)

2. Use the trigonometric identity cos(A) • cos(B) - sin(A) • sin(B) = cos(A + B) to simplify the numerator: = cos(25° + 15°) = cos(40°)

3. Move on to the denominator: cos(100°) + cos(20°)

4. Now, we can substitute the values and simplify further: cos(40°) / (cos(100°) + cos(20°))

Please note that I am assuming the trigonometric functions are in degrees. If they are in radians, you'll need to convert the angles to radians before performing the calculations.