Question

9cos128\sin64*sin26 .................

Answer 1

+++++++++++++++++++++++++++++++++++++

Answer 2

It appears that you have a mathematical expression that needs to be evaluated. Let's break it down step by step:

1. 9cos(128°): This represents the cosine of 128 degrees.
2. sin(64°): This represents the sine of 64 degrees.
3. sin(26°): This represents the sine of 26 degrees.

To evaluate the expression, we need to calculate the individual trigonometric values and then multiply them together:

1. First, let's convert the angles from degrees to radians:

   • 128 degrees = 128 * (π/180) radians
   • 64 degrees = 64 * (π/180) radians
   • 26 degrees = 26 * (π/180) radians

2. Now, calculate the trigonometric values:

   • cos(128°) ≈ cos(128 * π/180)
   • sin(64°) ≈ sin(64 * π/180)
   • sin(26°) ≈ sin(26 * π/180)

I'll calculate the approximate values:

cos(128°) ≈ cos(128 * π/180) ≈ -0.9914 sin(64°) ≈ sin(64 * π/180) ≈ 0.8988 sin(26°) ≈ sin(26 * π/180) ≈ 0.4384

3. Finally, multiply the results together:

9 * cos(128°) * sin(64°) * sin(26°) ≈ 9 * (-0.9914) * 0.8988 * 0.4384 ≈ -3.985

So, the value of the expression is approximately -3.985.