Q. dtdy=y+1 and y(0)=3. What is t when y=1 ?Choose 1 answer:(A) t=1(B) t=−ln2(C) t=ln2(D) t=ln4(E) t=0
Solve Differential Equation: First, we need to solve the differential equation dtdy=y+1 with the initial condition y(0)=3. We can separate variables and integrate.
Separate Variables: Separate the variables: y+11dy = dt.
Integrate Both Sides: Integrate both sides: ∫y+11dy=∫dt.
Find Constant of Integration: After integrating, we get ln∣y+1∣=t+C, where C is the constant of integration.
Calculate C: Using the initial condition y(0)=3, we can find C. Plug in t=0 and y=3 into ln∣y+1∣=t+C to get ln∣3+1∣=0+C.
Obtain Particular Solution: Calculate C: ln∣4∣=C, so C=ln4.
Find t for y=1: Now we have the particular solution ln∣y+1∣=t+ln4.
Simplify Equation: We want to find t when y=1. Plug y=1 into ln∣y+1∣=t+ln4 to get ln∣1+1∣=t+ln4.
Subtract ln4: Simplify the equation: ln2=t+ln4.
Combine Terms: Subtract ln4 from both sides to solve for t: t=ln2−ln4.
Simplify Fraction: Use the property of logarithms ln(a)−ln(b)=ln(ba) to combine the terms: t=ln(42).
Recognize ln(21): Simplify the fraction inside the logarithm: t=ln(21).
Recognize ln(21): Simplify the fraction inside the logarithm: t=ln(21).Recognize that ln(21) is the same as −ln2: t=−ln2.