Find the values of θ between 0° and 360° satisfying the equation 5 sin θ = -4.

Mathematics
Find the values of θ between 0° and 360° satisfying the equation 5 sin θ = -4.

ScanSolve AI Answer

Answer

500π81 cm3\dfrac{500\pi}{81}\ cm^{3}

Step 1: The volume VV of a right circular cone is given by the formula
V=13πr2h cm3,V = \frac{1}{3} \pi r^{2} h\ cm^{3},
where rr is the radius and hh is the height.

Given the constraint
r+h=5 cm.r + h = 5\ cm.

Solve for hh:
h=5r cm.h = 5 - r\ cm.

Step 2: Substitute h=5rh = 5 - r into the volume formula:
V=13πr2(5r) cm3.V = \frac{1}{3} \pi r^{2} (5 - r)\ cm^{3}.

Expand:
V=13π(5r2r3) cm3.V = \frac{1}{3} \pi (5 r^{2} - r^{3})\ cm^{3}.

Step 3: To find the maximum volume, compute the derivative dVdr\frac{dV}{dr}:
dVdr=13πddr(5r2r3).\frac{dV}{dr} = \frac{1}{3} \pi \frac{d}{dr} (5 r^{2} - r^{3}).

First, find the derivative of the inside:
ddr(5r2r3)=10r3r2.\frac{d}{dr} (5 r^{2} - r^{3}) = 10 r - 3 r^{2}.

So,
dVdr=13π(10r3r2) cm3/cm.\frac{dV}{dr} = \frac{1}{3} \pi (10 r - 3 r^{2})\ cm^{3/cm}.

Step 4: Set the derivative equal to zero to find critical points:
13π(10r3r2)=0.\frac{1}{3} \pi (10 r - 3 r^{2}) = 0.

Since 13π0\frac{1}{3} \pi \neq 0, solve
10r3r2=0.10 r - 3 r^{2} = 0.

Factor:
r(103r)=0.r (10 - 3 r) = 0.

Thus,
r=0 cmorr=103 cm.r = 0\ cm\quad or\quad r = \frac{10}{3}\ cm.

Step 5: Check the endpoints and critical points. Domain: 0<r<5 cm0 < r < 5\ \mathrm{cm} (since h>0h > 0).

At r0+r \to 0^{+}, V0 cm3V \to 0\ cm^{3}.
At r5r \to 5^{-}, V0 cm3V \to 0\ cm^{3}.

At r=103 cmr = \frac{10}{3}\ \mathrm{cm}, this is a candidate for maximum.

Corresponding hh:
h=5103=153103=53 cm.h = 5 - \frac{10}{3} = \frac{15}{3} - \frac{10}{3} = \frac{5}{3}\ cm.

Step 6: Compute the second derivative to confirm maximum:
d2Vdr2=13πddr(10r3r2)=13π(106r).\frac{d^{2}V}{dr^{2}} = \frac{1}{3} \pi \frac{d}{dr} (10 r - 3 r^{2}) = \frac{1}{3} \pi (10 - 6 r).

At r=103 cmr = \frac{10}{3}\ \mathrm{cm}:
106103=1020=10<0,10 - 6 \cdot \frac{10}{3} = 10 - 20 = -10 < 0,
so it is a local maximum.

Step 7: Substitute r=103 cmr = \frac{10}{3}\ \mathrm{cm} and h=53 cmh = \frac{5}{3}\ \mathrm{cm} into the volume formula:
V=13π(103)2(53) cm3.V = \frac{1}{3} \pi \left( \frac{10}{3} \right)^{2} \left( \frac{5}{3} \right)\ cm^{3}.

First, compute (103)2\left( \frac{10}{3} \right)^{2}:
(103)2=1009.\left( \frac{10}{3} \right)^{2} = \frac{100}{9}.

Then,
V=13π100953 cm3.V = \frac{1}{3} \pi \cdot \frac{100}{9} \cdot \frac{5}{3}\ cm^{3}.

Multiply:
100953=50027.\frac{100}{9} \cdot \frac{5}{3} = \frac{500}{27}.

So,
V=13π50027=500π81 cm3.V = \frac{1}{3} \pi \cdot \frac{500}{27} = \frac{500 \pi}{81}\ cm^{3}.

The maximum volume is 500π81 cm3\boxed{\dfrac{500\pi}{81}\ cm^{3}}.

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Quick Answer

The volume V of a right circular cone is given by the formula V = (1)/(3) r^2 h\ cm^3, where r is the radius and h is the height.

Find the values of θ between 0° and 360° satisfying the equation 5 sin θ = -4.
Mathematics

This mathematics problem involves applying core mathematical principles and formulas. Below you will find a complete step-by-step solution with detailed explanations for each step, helping you understand not just the answer but the method behind it.

ScanSolve AI Answer
Step 1: The volume V of a right circular cone is given by the formula V = (1)/(3) r^2 h\ cm^3, where r is the radius and h is the height. Given the constraint r + h = 5\ cm. Solve for h: h = 5 - r\ cm. Step 2: Substitute h = 5 - r into the volume formula: V = (1)/(3) r^2 (5 - r)\ cm^3. Expand: V = (1)/(3) (5 r^2 - r^3)\ cm^3. Step 3: To find the maximum volume, compute the derivative (dV)/(dr): (dV)/(dr) = (1)/(3) (d)/(dr) (5 r^2 - r^3). First, find the derivative of the inside: (d)/(dr) (5 r^2 - r^3) = 10 r - 3 r^2. So, (dV)/(dr) = (1)/(3) (10 r - 3 r^2)\ cm^3/cm. Step 4: Set the derivative equal to zero to find critical points: (1)/(3) (10 r - 3 r^2) = 0. Since (1)/(3) ≠ 0, solve 10 r - 3 r^2 = 0. Factor: r (10 - 3 r) = 0. Thus, r = 0\ cm or r = (10)/(3)\ cm. Step 5: Check the endpoints and critical points. Domain: 0 < r < 5\ cm (since h > 0). At r 0^+, V 0\ cm^3. At r 5^-, V 0\ cm^3. At r = (10)/(3)\ cm, this is a candidate for maximum. Corresponding h: h = 5 - (10)/(3) = (15)/(3) - (10)/(3) = (5)/(3)\ cm. Step 6: Compute the second derivative to confirm maximum: d^2Vdr^2 = (1)/(3) (d)/(dr) (10 r - 3 r^2) = (1)/(3) (10 - 6 r). At r = (10)/(3)\ cm: 10 - 6 · (10)/(3) = 10 - 20 = -10 < 0, so it is a local maximum. Step 7: Substitute r = (10)/(3)\ cm and h = (5)/(3)\ cm into the volume formula: V = (1)/(3) ( (10)/(3) )^2 ( (5)/(3) )\ cm^3. First, compute ( (10)/(3) )^2: ( (10)/(3) )^2 = (100)/(9). Then, V = (1)/(3) · (100)/(9) · (5)/(3)\ cm^3. Multiply: (100)/(9) · (5)/(3) = (500)/(27). So, V = (1)/(3) · (500)/(27) = (500 )/(81)\ cm^3. The maximum volume is (500)/(81)\ cm^3.