Help needed with direction angles and vector equations

agenttiny200
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Homework Statement



A line has direction angles 60°, 45°, 60° and passes through the point
(1, -2, 5). Determine the vector equation of this line.

Homework Equations



I honestly have no clue. My teacher gave a hint it has to do with trig (as in the trig ratios) and the unit vector formula, but I don't see how they mix.

The Attempt at a Solution



Tried everything except the right way for the last week, resulting in dead ends.
 
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if no one has a clue, it would help to mention that, proving to my teacher that he should just give me the answer.
 
And I am serious when I say I have been trying for a week to solve it, I am not trying to get by easily. posting my questions here is kind of a last resort, for a question that I am really stuck on.
 
Prove $$\int\limits_0^{\sqrt2/4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx = \frac{\pi^2}{8}.$$ Let $$I = \int\limits_0^{\sqrt 2 / 4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx. \tag{1}$$ The representation integral of ##\arcsin## is $$\arcsin u = \int\limits_{0}^{1} \frac{\mathrm dt}{\sqrt{1-t^2}}, \qquad 0 \leqslant u \leqslant 1.$$ Plugging identity above into ##(1)## with ##u...
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