Q. Determine h(t) given that h′′(t)=24t2−48t+2,h(1)=−9 and h(−2)=−4.
Integrate h′′(t): To find h(t), we need to integrate h′′(t) twice. The given second derivative is h′′(t)=24t2−48t+2. Let's integrate this to find the first derivative h′(t).
Find h′(t): The integral of 24t2 with respect to t is (24/3)t3=8t3. The integral of −48t with respect to t is (−48/2)t2=−24t2. The integral of 2 with respect to t is 2t. We also add a constant of integration, 24t20. So, 24t21.
Integrate h′(t) to find h(t): Now we integrate h′(t) to find h(t). The integral of 8t3 with respect to t is (8/4)t4=2t4. The integral of −24t2 with respect to t is (−24/3)t3=−8t3. The integral of h(t)0 with respect to t is h(t)2. We also add another constant of integration, h(t)3. So, h(t)4.
Use h(1)=−9: We have two initial conditions: h(1)=−9 and h(−2)=−4. We will use these to solve for the constants C1 and C2. First, let's use h(1)=−9. Plugging in t=1, we get h(1)=2(1)4−8(1)3+(1)2+C1(1)+C2=2−8+1+C1+C2=−5+C1+C2. Since h(1)=−9, we have −5+C1+C2=−9.
Use h(−2)=−4: Now let's use h(−2)=−4. Plugging in t=−2, we get h(−2)=2(−2)4−8(−2)3+(−2)2+C1(−2)+C2=32+64+4−2C1+C2=100−2C1+C2. Since h(−2)=−4, we have 100−2C1+C2=−4.
Solve system of equations: We now have a system of two equations:1) −5+C1+C2=−92) 100−2C1+C2=−4Let's solve this system for C1 and C2.
Subtract equations to eliminate C2: Subtract equation 1) from equation 2) to eliminate C2: (100−2C1+C2)−(−5+C1+C2)=−4−(−9) 95−3C1=5 −3C1=5−95 −3C1=−90 C1=30
Find C1: Now that we have C1, we can substitute it back into equation 1) to find C2: -5+30+C2=−9 25+C2=−9 C2=−9−25 C2=−34
Find C2: We have found C1=30 and C2=−34. Now we can write the final form of h(t):h(t)=2t4−8t3+t2+30t−34.
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