Skip to content
🤔prompts chat🧠
🔍
question:Find the equation of the tangent line to the curve y=e^{5x}+2 at the point (0,3).

answer:First, we find the derivative of the given curve, y=e^{-5x}+2. The derivative is y'=-5e^{-5x}. Next, we find the slope of the tangent line at the point x=0. Substituting x=0 into the derivative, we get y'=-5e^{-5*0}=-5. Now, we know that the tangent line has a slope of -5 and passes through the point (0,3). Using the point-slope form of a linear equation, y-y_1=m(x-x_1), we can find the equation of the tangent line. Substituting the slope m=-5 and the point (x_1,y_1)=(0,3) into the point-slope form, we get y-3=-5(x-0). Simplifying this equation gives us y=-5x+3. Therefore, the equation of the tangent line to the curve y=e^{-5x}+2 at the point (0,3) is boxed{y=-5x+3}. This problem tests the understanding of the geometric meaning of a derivative: the slope of the tangent line to the curve at a given point. It also tests computational skills and is considered a basic problem.

question:Carlson has three boxes, each containing 10 candies. One box is labeled with the number 4, another with the number 7, and the third with the number 10. In one operation, Carlson performs the following two steps sequentially: Takes from any box the number of candies equal to the number written on it. Eats 3 candies from those taken, and puts the remaining candies into any other box. What is the maximum number of candies Carlson can eat as a result of several such operations?

answer:To determine the maximum number of candies that Carlson can eat by performing the described operations, we need to examine the pattern and constraints of these operations. 1. **Initialization**: Carlson starts with three boxes, each containing 10 candies. The numbers written on the boxes are: 4, 7, and 10. 2. **Understanding the operations**: - In each operation, Carlson will take a certain number of candies (denoted by the number on the box) from any one box. - He then eats 3 candies from the taken bunch. - The remaining candies (after eating 3) are placed into any of the other two boxes. 3. **Divisibility by 3**: Since Carlson eats 3 candies in each operation, the total number of candies eaten will always be a multiple of 3. This is a crucial observation because it sets the stage for proving the upper limits based on the total number of candies available. 4. **Total candies**: - Initially, there are (3 times 10 = 30) candies in total. - Given the process described, the object is to show that the maximum Carlson can eat is less than or equal to 27. 5. **Proof by contradiction**: To show that Carlson cannot eat 30 candies, assume that he could: - Before the last operation, there would be exactly 3 candies left. - Each of the numbers on the boxes (4, 7, 10) is greater than 3. Therefore, Carlson cannot perform the last operation to eat the remaining candies. This is a contradiction since he cannot make a move with these numbers if each box has at most 3 candies left. 6. **Construct an example showing Carlson can eat 27 candies**: - Here we provide a sequence of steps Carlson can follow to consume exactly 27 candies: [ begin{align*} text{Initial state}: & (10, 10, 10) text{After 1st operation}: & (6, 13, 10) quad text{(take 4 from the first box, eat 3, place 1 in the second)} text{After 2nd operation}: & (6, 6, 17) quad text{(take 7 from the second box, eat 3, place 4 in the third)} text{After 3rd operation}: & (6, 6, 7) quad text{(take 10 from the third box, eat 3, place 7 back in the same box)} text{After 4th operation}: & (3, 9, 7) quad text{(take 3 from the first box, eat 3, no leftover)} text{After 5th operation}: & (3, 2, 14) quad text{(take 7 from the second box, eat 3, place 4 in the third)} text{After 6th operation}: & (3, 2, 11) quad text{(take 10 from the third box, eat 3, place 7 back in the same box)} text{After 7th operation}: & (0, 2, 14) quad text{(take 3 from the first box, eat 3, no leftover)} text{After 8th operation}: & (0, 0, 16) quad text{(take 2 from the second box, eat 3, place 13 back in the third)} text{After 9th operation}: & (0, 0, 6) quad text{(take 10 from the third box, eat 3, place 7 in another box)} text{After 10th operation}: & (0, 0, 3) quad text{(take 4 from the last box, eat 3, place 1 back)} text{After 11th operation}: & (0, 0, 0) quad text{(take 3 from the last box, eat 3)} end{align*} ] This sequence shows that Carlson consumes exactly (3 times 9 = 27) candies. # Conclusion: [ boxed{27} ]

question:Given that the right focus of an ellipse is F(m,0), the left and right directrices are l_{1}: x=m1, l_{2}: x=m+1, respectively, and l_{1}, l_{2} intersect with the line y=x at points A and B, respectively. (1) If the eccentricity of the ellipse is frac{sqrt{2}}{2}, find the equation of the ellipse. (2) When overrightarrow{AF} cdot overrightarrow{FB} < 7, find the range of the eccentricity of the ellipse.

answer:(1) Since the right focus of the ellipse is F(m,0), the focus is on the x-axis. Let the equation of the ellipse be: frac{x^2}{a^2} + frac{y^2}{b^2} = 1 quad (a > b > 0) From this, we have c=m. The directrix equations are x=frac{a^2}{c}=m+1. Thus, we obtain a^2=m(m+1) and b^2=m. Given the eccentricity e=frac{c}{a} = sqrt{1-frac{b^2}{a^2}} = frac{sqrt{2}}{2}, we can derive b=c, which leads to m=1. Therefore, a=sqrt{2} and b=1. Hence, the equation of the ellipse is: boxed{frac{x^2}{2} + y^2 = 1} (2) From the problem, we can determine that A(-m-1,-m-1) and B(m+1,m+1). Thus, overrightarrow{AF} = (2m+1, m+1) and overrightarrow{FB} = (1, m+1). Calculate the dot product: overrightarrow{AF} cdot overrightarrow{FB} = 2m+1+(m+1)^2 = m^2 + 4m + 2 < 7. Solving for m, we get: boxed{0 < m < 1}. The eccentricity e = frac{c}{a} = frac{m}{sqrt{m(m+1)}} = frac{1}{sqrt{1+frac{1}{m}}}. Therefore, the range of the eccentricity is: boxed{left(0, frac{sqrt{2}}{2}right)}

question:Two numbers are in the ratio 8 to 3. If the sum of numbers is 143 , find the bigger number?

answer:Let the two numbers be 8x and 3x, where x is a common factor. According to the problem, the sum of these two numbers is 143. So, we can write the equation as: 8x + 3x = 143 Combining like terms, we get: 11x = 143 Now, we solve for x: x = 143 / 11 x = 13 Now that we have the value of x, we can find the bigger number (which is 8x): 8x = 8 * 13 8x = 104 Therefore, the bigger number is boxed{104} .

Released under the BERT License.

has loaded