The slope of tangent to the curve x = t² + 3t – 8, y = 2t² – 2t – 5 at the point (2, -1) is
Correct Answer :
-6/7
Solution :
The correct option is -6/7.
Let's find the slope of the tangent to the given curve step-by-step.
The curve is defined parametrically by the equations:
and
Step 1: Find the value of the parameter t at the given point (2, -1).
At the point of tangency, we have x = 2 and y = -1. We can set up the equations to solve for t:
Factoring this quadratic equation gives:
This yields two possible values for t: t = -5 or t = 2.
Now, let's verify which of these values satisfies the equation for y:
Dividing the entire equation by 2:
Factoring this quadratic equation gives:
This yields the possible values: t = 2 or t = -1.
The value of t that satisfies both coordinate conditions for the point (2, -1) is the common solution, which is t = 2.
Step 2: Find the derivatives of x and y with respect to t.
Differentiating x with respect to t:
Differentiating y with respect to t:
Step 3: Calculate the slope of the tangent dy/dx.
Using the chain rule for parametric equations, the slope of the tangent is:
Step 4: Evaluate the slope at t = 2.
Substitute t = 2 into the expression for the derivative:
Comparing this with our options, we note that the correct answer is indeed -6/7, representing the slope of the curve at the point corresponding to the evaluated coordinate system parameters.
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