# 20 Most Recent Casio FX991ES Scientific Calculator Questions & Answers

You cannot use the two words in the same sentence. To use the hyperbolic functions, press the HYP key. The display will show you what follows.
1: hyperbolic sine, 2: hyperbolic cosine, 3: hyperbolic tangent, and their inverses.
To calculate the hyperbolic cosine of the number 27/3, press 1 in the first screen capture, you get cosh(. Complete the expression and press=

Casio FX991ES... | Answered on Jan 28, 2019

If the quadratic equation has no roots, you cannot find the roots. The discriminate is negative, so if we attempt to use the quadratic equation, we get no roots.

For example, y=x^2 +0x + 3

a=1, b=0, c=3

(-b+/- sqrt(b^2 -4ac))/2a

Substituting in the numbers, we get

x= (-0 +/-sqrt(0^2 - 4(1)3))/2
x= (0 +/- sqrt (-12))/2

We cannot do the square root of -12. Therefore, there are no roots. This is the same as having no x-intercepts. The discriminant is b^2-4ac. In this case it is -12. Thus, there are no real roots.

However, you can still determine the maximum or minimum, the vertex, the axis of symmetry, the y-intercept and the stretch/compression. With this information you can graph the equation.

In this case, the y-intercept is 3, the vertex is at (0,3), the axis of symmetry is x=0, the minimum value of the function is 3.

Good luck.

Let me know if you have any questions.

Paul

Casio FX991ES... | Answered on Jan 02, 2019

Hi, You did not put the batteries in correctly. Please replace in correct + to + and - to -....This should fix this issue.

Casio FX991ES... | Answered on Oct 04, 2018

See captured images below

Casio FX991ES... | Answered on Apr 28, 2016

Turn calculator on.
Press SHIFT Mode
Scroll Down to go to next page
Press 8, then use left arrow to dim or right arrow to darken the screen.
See the screen capture below (these are for the FX82ESPlus)

For your calculator, it will be 8 CONT

Casio FX991ES... | Answered on Apr 22, 2016

Guys please tell me how can i truncate the entire fractional part (Explicit integer Type conversion) in my fx991 es calculator?it helps me a lot in solving my cryptography problems easily...

Casio FX991ES... | Answered on Dec 21, 2014

The calculator may have been subjected to a hacking procedure found on the Internet. Find a way to undo the hack or buy another calculator. Or hold it upside down to read the display (once you get the last result.)

Casio FX991ES... | Answered on Aug 17, 2014

The calculator was probably subjected to a hacking procedure. Buy another one.

Casio FX991ES... | Answered on Jul 15, 2014

Use nPr, which is the shifted function of the multiply key. For example, to find the number of permutations of six items taken three at a time, press 6 SHIFT nPr 3 =

Casio FX991ES... | Answered on Jun 15, 2014

Use nCr (the shifted function of the divide key). For example, to find the number of combinations of five things taken three at a time, press 5 SHIFT nCr 3 = and see 10.

Casio FX991ES... | Answered on May 04, 2014

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