Incorrect numerical integration, how to fix?

I am trying to solve for the average and rms of a function, y(t), and upon numerical integration, I am not finding the correct answers.

MATLAB EDITOR:

%   Determine the AVERAGE and RMS values for the function:
%   y(t) = 25 + 10sin6pi(t)     over:
%   a) 0 to 0.4 sec
%   b) 0.4 to 0.6 sec
%   c) 0 to 1/6 sec
%   d) 0 to 26 sec

clc
clear all
close all
format short

%upper and lower limits of integration
a1=0;
a2=0.4;
b1=0.4;
b2=0.6;
c1=0;
c2=1./6;
d1=0;
d2=26;

%function
fun=@(t)(25+10.*sin(6*t*pi))
fun2=@(t)(25+10.*sin(6*t*pi)).^2

%computation
f_avg_a=(1/(a2-a1)).*(integral(fun,a1,a2))
f_rms_a=sqrt((1/(a2-a1)).*(integral(fun2,a1,a2)))

MATLAB COMMAND WINDOW:

fun =

function_handle with value:

@(t)(25+10.*sin(6*t*pi))

fun2 =

function_handle with value:

@(t)(25+10.*sin(6*t*pi)).^2

f_avg_a =

25.9164

f_rms_a =

26.8118

MY HANDHELD CALCULATOR SHOWS THAT THE ANSWERS SHOULD BE

f_avg_a= 25.657

f_rms_a= 25.6598

Answer 1

[the cyclist]

MATLAB's result is correct. You must have made a mistake on your calculator.

You can verify this calculation that I entered into WolframAlpha.

It is also straightforward to carry out this integral with pencil and paper.