Answer:
2.63274768567
Step-by-step explanation:
First, note that 3.1415... is p, so 2(3.1415...) is 2pi and 4(3.1415...) is 4pi.
2pi and 4pi are full rotations, which will lead to the same cosine (i.e. cos(x) = cos (x+2pi) = cos(x+4pi) = ... = cos (x+2k*pi)).
So, the expression equals cos0.5 + cos 0.5 + cos0.5 = 3cos0.5 = 3(0.87758256189) = 2.63274768567
I hope this helps! :)
Let's solve your equation step-by-step.<span><span><span><span>2<span>x2</span></span>−<span>3x</span></span>−4</span>=0</span>Step 1: Use quadratic formula with a=2, b=-3, c=-4.<span>x=<span><span><span>−b</span>±<span>√<span><span>b2</span>−<span><span>4a</span>c</span></span></span></span><span>2a</span></span></span><span>x=<span><span><span>−<span>(<span>−3</span>)</span></span>±<span>√<span><span><span>(<span>−3</span>)</span>2</span>−<span><span>4<span>(2)</span></span><span>(<span>−4</span>)</span></span></span></span></span><span>2<span>(2)</span></span></span></span><span>x=<span><span>3±<span>√41</span></span>4</span></span><span><span>x=<span><span>34</span>+<span><span><span><span>14</span><span>√41</span></span><span> or </span></span>x</span></span></span>=<span><span>34</span>+<span><span><span>−1</span>4</span><span>√<span>41</span></span></span></span></span>
It looks like the differential equation is
Check for exactness:
As is, the DE is not exact, so let's try to find an integrating factor <em>µ(x, y)</em> such that
*is* exact. If this modified DE is exact, then
We have
Notice that if we let <em>µ(x, y)</em> = <em>µ(x)</em> be independent of <em>y</em>, then <em>∂µ/∂y</em> = 0 and we can solve for <em>µ</em> :
The modified DE,
is now exact:
So we look for a solution of the form <em>F(x, y)</em> = <em>C</em>. This solution is such that
Integrate both sides of the first condition with respect to <em>x</em> :
Differentiate both sides of this with respect to <em>y</em> :
Then the general solution to the DE is