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Need help with derivative question!!!

linapril

New member
Dec 21, 2012
23
I've solved half the question (I think), but then gotten stuck... Can someone help me out?

The question:
The tangent to the curve y=ae2x + bx on the point (0,4) has the gradient k=3. Determine the values of a and b.

My solution:
y' = 2ae2x+b
y'(0) = 3
2ae2(0)+b)=3
2a+b=3
b=3-2a

And this is where I don't know how to proceed...
Would appreciate some help!
 

MarkFL

Administrator
Staff member
Feb 24, 2012
13,775
You have correctly done the hard part of differentiation. (Sun)

You also know $y(0)=4$. This will give you a second equation in the two unknowns, and then you will be able to determine the solution.