Home > Trigonometry > Solving Trigonometric Equations

For what value of #x# does #sin(x)+cos(x)=x#?

Answer 1

Assuming we are working in radians then
#color(white)("XXX")x~~1.2587#

I suspect this question is invalid, but in case it is not (and in order to clear it from the unanswered question list), here is what I was able to come up with:

If I graph #f(x)=sin(x)+cos(x)# and #f(x)=x#
I get an intersection point that is between #x=1.2# and #x=1.3#
#arctan# to get a better solution but, since I was uncertain that the question was even correct, this is the best I could do without excessive analysis.

By signing up, you agree to our Terms of Service and Privacy Policy

Answer 2

Madelyn Adams

For (x \approx 0.739) radians (or (x \approx 42.4^\circ) degrees), the equation ( \sin(x) + \cos(x) = x ) holds true.

By signing up, you agree to our Terms of Service and Privacy Policy

Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.