Trigo: A boy pushes a ladder up from horiz. on the ground.

[SKY KEUNG]

CAN SOMEBODY HELP?
I can't do b part.
i try to express the angles to half angles, but i fail.

 

[mmm4444bot]

I can't do b part.

I used the Sum-to-Product identities to express cot([α + β] / 2) as a ratio (i.e., difference of sine terms in the numerator and difference of cosine terms in the denominator).

In the equation y = x * cot([α + β] / 2), I substituted:

• my ratio for the cotangent factor
• your L * [sin(β) - sin(α)] for y
• your L * [cos(α) - cos(β)] for x

Then, one division on each side finished it. :cool: